Thea Queen

"I'm gonna miss you so much." "You'll be with me the whole time."

- Oliver Queen and Thea Queen before she leaves Star City

Thea Dearden Queen (born January 21, 1995 ), also known as Mia during her time in Corto Maltese, is the daughter of the late Malcolm Merlyn and the late Moira Queen, the adoptive daughter of the late Robert Queen (though treated unquestionably as his daughter throughout his life), the younger maternal half-sister of the late Oliver Queen, the younger paternal half-sister of Saracon and the late Tommy Merlyn, the aunt of William Clayton and Mia Smoak and the half-sister-in-law of Felicity Smoak. After learning how to fight from Malcolm and being saved from near-death by a Lazarus Pit, Thea became a vigilante and member of Team Arrow, using her brother's nickname for her, Speedy, as her codename. After one year, she decided to leave the team in order to find her true self.

Thea was comatose for six months following Lian Yu's destruction after the battle against Prometheus's team, but she has since recovered. When Roy was captured by Ricardo Diaz, Thea donned her vigilante mantle to help rescue him. With encouragement from Oliver, Thea decided to leave with Roy and Nyssa al Ghul to find and destroy Lazarus Pits that were discovered by her late biological father. After succeeding in this mission, Thea became the co-leader of League of Heroes alongside Talia al Ghul.

Early life
Thea was born on January 21, 1995 to Malcolm Merlyn and Moira Queen. Although Malcolm was unaware that she was his daughter and Thea was likewise left in the dark, Robert Queen was aware, though he still loved her like his own. Thea was especially close to Robert, thinking the world of him.

When Thea was four years old, she found a stray cat and brought it home. Moira protested that they couldn't keep it but Thea refused to listen, firmly declaring the cat was going to be her pet. When Robert came home from work later that day and saw what was going on, he sat Thea down and told her that the "cat" was actually a tiger, and they couldn't keep it because it needed to be returned home. Thea understood.

Growing up, Thea idolized her older brother Oliver. They were very close and according to Oliver, Thea was a fast runner and he would always chase after her, resulting in him giving her the nickname "Speedy". Every Christmas, Oliver and Thea would compete to see who could eat the holiday candy canes the fastest, which Thea allegedly always won, though Oliver would claim she cheated. Thea was also close to Laurel Lance and Tommy Merlyn, who were like siblings to her (and the latter was really her paternal-half brother).

As a child, Thea was very creative and loved to draw and color, to the point that Robert would order her many boxes of crayons "by the truckload." Thea would even draw on the walls of her home, much to her mother's fond exasperation. When she was young, Thea once fell off her horse, breaking her arm, and was hospitalized. When Thea attended her first boy-girl dance at school, Robert disapproved of her dress and terrified her date.

In 2007, when Thea was 12 years old, Robert and Oliver were both presumed dead on the Queen's Gambit. With her mother subsequently becoming increasingly emotionally distant out of her own grief, Thea was devastated, feeling alone, depressed, and disconnected from the world. By the time she was 15, Thea fell into a life of drugs and partying to fill the void left by her father and brother.

In February 2010, Thea went to visit Oliver and Robert's graves after school, reminiscing to them about her studies and Moira growing closer to Walter Steele. Her drug dealer came along and sold her some pills. When Tommy then arrived, he became furious and scolded Thea, who retorted that he wasn't her brother. That night, she snuck into Tommy's 25th birthday party using a fake ID. Briefly catching up with Tommy and Laurel, Thea promised them she would behave. Suddenly, her drug dealer fell from the balcony with his neck snapped (by Oliver). The cops arrived and after Thea gave her statement, she was cornered by Detective Quentin Lance, who pointed out she was too young to be at a party like this. Tommy covered for Thea, claiming he invited her. Quentin caustically ranted that he didn't know if Thea was becoming more like Oliver or his late daughter, Sara Lance, until Laurel pulled him aside. Thea was taken home and the next day, she delivered flowers to Oliver and Robert's graves.

Oliver Queen's return
When Oliver was rescued from a deserted island after five years, Thea was one of the first people to welcome her brother home with open arms. However, she was later surprised and disappointed when he expressed unhappiness and disapproval over Thea's party girl lifestyle, which Oliver himself used to lead.

A week later, Thea and her family watched a news report on the city's vigilante, "The Hood". She was somewhat intrigued by the figure, indifferent to the danger he potentially posed, in contrast to Moira's wariness. Thea then declined to attend Oliver's legal resurrection, snarking that "the first four times of [him] in court was enough for [her]". That night as she prepared to go out partying, Oliver tried to protest that Robert wanted better for her. Thea simply countered that "dead people don't want anything" and called Oliver out over neglecting his family since returning home. Later, Thea accidentally entered Oliver's bedroom whilst he was getting dressed and spotted his scars for the first time, much to her horror. When Oliver admitted he wasn't ready to talk about the island, Thea took her brother to his and their father's graves on the Queen Mansion's grounds. Tearfully reflecting how the last five years weren't easy for her either, she begged Oliver to let someone, if not her, in on his pain. Thea later attended the groundbreaking of Queen Consolidated's Applied Sciences division and listened to Oliver's impromptu speech.

Thea was brought home by the police after a night of drunken partying with her friends that led to breaking and entering a boutique. Unrepentant, Thea suggested her mother shop at the store whilst paying off the owner and convinced Moira to let the former take a sick day from school. The next day, she was later grounded by her mother, much to her frustration. Despite this, Thea partied at the nightclub Poison, where she bumped into Oliver and the two had an argument over the company Thea was keeping. Out of spite, Thea disclosed to Oliver that his friends, Laurel and Tommy, had been sleeping together in his absence and stumbled off. Later after a mother-daughter talk with Moira about Robert and the past, Thea began to tone down her wild behavior and appeared at the Unidac Industries auction to support Walter. When the building was attacked by a sniper aiming to kill Walter, Oliver urged Thea and Moira to leave with his bodyguard, John Diggle.

After the auction, Thea bonded with Oliver while watching TV as they discussed Laurel, and how Oliver could get back into her "good-books" again. She advised her brother to just continue to be his "new self". A couple nights later, Thea was surprised to see Oliver smiling, to which he admitted her advice about Laurel was working. Pleased at the prospect of her brother and Laurel potentially getting back together, Thea teased Oliver about letting her know when he wanted to find "trendy places to propose".

Thea and her family were worried for Oliver after charges of being the vigilante were brought against him by Detective Quentin Lance. During Oliver's prison-themed party, Thea expressed how she didn't want to lose her brother again, having been deeply impacted by his absence. Oliver reassured her at the end that she wouldn't.

Thea developed a crush on Tommy after he came asking her for romantic advice regarding a girl he wanted to impress. However, the situation became very awkward when she realized Tommy meant Laurel instead of her. Thea ended up getting drunk at a benefit for Laurel's employer, CNRI, and Tommy took her home. Embarrassed, she tearfully apologized for making a scene, but Tommy and Laurel assured her it was okay.

Thea called Oliver to remind him that he was supposed to have lunch with Moira, telling him to "bite the bullet and have a Cobb salad with the woman". Later on, Thea went to see her mother at Starling Hospital when Moira was injured in a shooting. She told Oliver off for leaving their mother to go after the shooter. Thea stayed home that night with Moira after Oliver told her he had a "business meeting". She confided in her mother about how she wishes that Oliver would just tell them what was wrong. Moira suggested they should simply try and understand how much he has changed.

Thea asked Walter for a ride to school, commenting that they could just buy her a convertible to save them the trouble.

Oliver talked to Thea about their lack of Christmas decorations, and she revealed how they hadn't really celebrated Christmas since Oliver and Robert disappeared. Thea was later seen at Big Belly Burger with Oliver, discussing why there was no Christmas Party when Thea's friend Shane showed up. Oliver later walked in on Thea and Shane at the Christmas Party and caught them making out with some clothes off. Oliver told the boy, "Hit the road", much to Thea's annoyance. Later that night, Thea, Walter and Moira visited the hospital after Oliver was injured in a motorcycle crash. Thea apologized to Oliver for what she said and two agreed to restart their relationship. Thea brought two candy canes for herself and Oliver to snack on as a Christmas gift.

Six weeks after Walter's mysterious disappearance, Thea was concerned about her mother shutting everyone out, including her and Oliver. She confided in Oliver that Moira was acting the same way as when he and Robert were presumed dead. Thea later tried to convince her mother to leave her room and go out with her. Afterwards, Thea visited Oliver when his club burnt down and wondered why he was smiling.

As she was preparing for her 18th birthday party, Thea began to believe that her mother was having an affair with Malcolm Merlyn. Upon seeing the two talking at her party, Thea angrily told her mother off, wishing she died on the Gambit instead of Robert. Thea then stormed out, taking her new Maserati for a joyride. However, she was involved in a car crash and taken to the hospital. Oliver later discovered that Thea crashed because she was high on a drug called Vertigo. After being discharged the next day, Thea was arrested for driving under the influence of narcotics.

Due to the rampant use of Vertigo in Starling City, Judge Brackett, who was overseeing Thea's trial, decided that the best way to discourage the drug's use was to sentence Thea to hard time and show that not even the rich can escape the law. Oliver decided to take down Cecil Adams/The Count so as to take heat off his sister and talked to Laurel about getting her father to use his connections to help Thea. Quentin was able to get Thea a deal where she was put on probation for two years and had to work community service for 500 hours under the watch of a guardian. The plan was for her to work at CNRI under Laurel's supervision. However, Thea stubbornly refused the deal just to hurt her mother. To convince her, Oliver revealed that Robert had in fact cheated on Moira and admitted to not being the father they believed him to be. Upon overhearing Moira confirm this, a remorseful Thea apologized to her mother. She then decided to accept Laurel's offer and work with her.

During her orientation at CNRI, Thea complained to Laurel about how long she had left to work, seeing herself as a "court-ordered slave" and asking "how [her 500 hours of community service was] not cruel and unusual punishment". Thea then learned from Laurel's coworker, Anastasia, that Cyrus Vanch was released from prison.

When Oliver arrived home the morning after Moira was attacked by the vigilante, Thea was with her mother and the cops. She demanded to know where Oliver had been all night, as she'd tried to call him many times.

While out on a lunch break from CNRI with Laurel, Thea's purse was stolen. Using a wallet chain the thief left behind, Thea discovered his name was Roy Harper. After hearing Roy's story in the police station, Thea took pity on him and dropped the charges. She then tracked Roy down at his home in the Glades to retrieve her purse. They had a brief talk, during which Thea informed Roy that her life isn't perfect either, as she was dealing with her father dying, her stepfather going missing, and her brother struggling with his own demons. Before she left, Roy advised Thea to stay out of the Glades and not "fall for every sob story a guy like [him] tells the police."

A couple weeks later, Thea met Roy again and offered him a job at Oliver's club, Verdant. Roy seemingly accepted, only to brush her off. Later though, Roy saved Thea from some thugs. In doing so, he was stabbed, and Thea took him to the hospital. When Roy grew nervous about getting a shot, Thea advised him to just take his mind off of it, to which he responded that he didn't like needles. When the doctor gave Roy the shot, Thea kissed Roy to distract him from it.

Thea and Roy began a romantic relationship, though she was frustrated by his ties with crime in the Glades. They eventually had an argument about this, which was interrupted when the Savior ambushed and kidnapped Roy. Thea attempted to intervene, but was knocked aside. As the Savior broadcasted his interrogation of Roy on Glades Betrayed, Thea watched from Verdant and broke down in tears, fearful for Roy's fate. Oliver comforted her, promising that Roy would not die. After Roy was saved by the Hood, Thea reunited with him at Verdant.

When Roy told her he had to find the Hood, Thea told him she would help.

Thea continued to help Roy find the Hood but Oliver told Roy not to and Thea agreed with him but Roy didn't, leading to them briefly splitting.

Thea witnessed Moira announcing the Undertaking and went to the Glades to find Roy. She threw an empty glass bottle at a gang member who was about to shoot him. As the two began driving away, Roy saw a group of people trapped on a bus and went to help them, despite Thea's warning that the Markov Device could go off any second. Roy told Thea that he couldn't leave anyone behind and urged her to get out of the Glades. By the time the earthquake started, Thea and Roy were both able to make it out safely.

Sometime after the Undertaking, Thea attended Tommy's funeral after the latter died whilst saving Laurel.

After the Undertaking
Five months after the earthquake, Thea got her act together, taking over Oliver's role as owner of Verdant. She is still dating Roy, but they often fought due to Roy trying to fill in the Hood's role. When Oliver returned to Starling City, Thea was happy to see her brother again, who was impressed by how much his sister changed. Thea shut Oliver down when he attempted to persuade her to visit Moira in prison. Later, Roy also made the same attempt, only to be shut down as well. Verdant was attacked by the Hoods, who were looking for Oliver. Thea and the other patrons watched on as Roy tried to fight them off. Upon discovering Thea, the Hoods kidnapped her and fled. Thea was held captive in an abandoned church in the Glades. While the Hoods argued on what to do with her, Thea defended her mother from their accusations, realizing Moira was a victim of circumstances and had no choice but to follow Malcolm's orders. When one of the Hoods decided to kill Thea, the Arrow (Oliver) saved her and told her to run. Afterwards, Thea visited Moira in prison for the first time in months, telling her about her near-death experience, and reconciled with her mother.

After Roy was arrested during an attempt to fend off some hijackers, Thea gave Roy an ultimatum, which he later accepted, telling her that he chose her and was done being the hero, (though he was secretly in an agreement with the Arrow).

During Moira's trial, both Oliver and Thea were stunned when ADA Adam Donner wanted to seek the death penalty for Moira. Oliver assured Thea that they were both going to help their mother to fight for her life. Later, they both watched the news reporting Laurel and Quentin's kidnapping.

During Oliver's "cash for guns" event, Thea met Sin Simone. When the event was crashed by The Mayor, Roy and Thea evaded the resulting shootout by hiding behind a car. When Sin was injured by a bullet, Thea went to get help for her. Later, both Roy and Thea stayed in the hospital by Sin's side. Sin commented to Thea that she was dating a "moron" and Thea agreed. Sin then admitted to Roy that she liked Thea.

Thea was furious when her mother decided to take the deal that Adam offered. She and Oliver encouraged Moira to fight for her life. Later when Thea and Oliver visited her again, they assured Moira that she will not lose them and they will stick by her no matter what secret their mother is hiding, which led Moira to agree to refuse the deal.

Thea went to the police station to bail Roy out of prison. Later, Moira's attorney, Jean Loring, visited Thea at Verdant and warned her that her relationship with Roy, a known felon, is hurting her mother's case, prompting Thea to break up him. Later, Thea went to visit her mother and was surprised to find Roy there. Moira told Thea that she has flourished the past year, which had a lot to do with Roy, and assured her daughter that her personal life is not going to affect the former's case, bringing Roy and Thea back together.

Thea, Oliver, and Roy were present during Moira's trial's opening. When Thea was brought to the stand, Adam Donner questioned her for not visiting her mother for months. He pointed out that Thea felt angry with her mother, which was the reason that it took a long time. Later in the club, Roy noticed Thea's anger and brought her boxing gloves, telling her to punch him as a release. Thea did so and collapsed against him in tears, feeling she ruined her mother's case. During the second half of the trial when Moira refused to testify, both her children questioned her reasons, which led Moira to admit to having an affair with Malcolm, much to Thea's dismay. Later, Thea and Oliver were waiting for the verdict when Oliver ran off to go after Count Vertigo, much to Thea's confusion. After Oliver returned, he and Thea were overjoyed when Moira was found not guilty and acquitted of all charges.

Thea and Oliver welcomed Moira home before Thea headed out with Roy to meet Sin. Roy was surprised that Thea not only approved of but also decided to join Roy and Sin search for the latter's missing friend, Max Stanton. The three later head to his flat to investigate and discovered that his disappearance was related to Sebastian Blood's blood drive. During Moira's party when Roy received a call from Sin about Max, he left and insisted that Thea should stay with her mother. After the party, Moira was about to tell Thea the truth about her parentage but changed her mind and settled for saying that she loves her.

After Roy got shot with an arrow, Thea locked herself in her room along with Sin, concerning Moira, who asked Oliver to check on her. Upon the finding out the truth, Oliver removed the arrow from Roy's leg and warned the three of them to stay out of trouble. Sin asked Thea if she is really going to let this go, which Thea refused, stating that she is doing things her way. Later, Thea and Sin sought Laurel's help in regard to Max's case. Laurel was able to uncover information regarding the blood drive, telling them that that they can't get a warrant to investigate more regarding whether Max was on drugs or not. After Roy woke up in Thea's room, Thea and Sin rushed to see him, concerned that he was chasing down the Arrow.

Thea was present during Oliver’s speech about Blood, after which she joked about Oliver’s friendship with the politician due to Blood's relationship with Laurel. Oliver then changed the subject, asking Thea about Roy's condition. Thea sarcastically recounted how Roy came to work on time. Later when Thea came to check on Roy, she noticed him acting strange when she confronted him, Roy initially pushed her away before admitting that she is the one who is helping him getting through the hard times. The two shared a kiss and began to make out, but Roy was suddenly injured by falling glass. Thea rushed to get the first aid kit. Later, Thea, Moira, and Roy attended Blood's Unity Rally. Suddenly, the event was attacked by "Shrapnel" and Thea witnessed Roy save Moira from falling debris. Afterwards, Thea confronted him later about it but he didn't give her a straight answer, leaving Thea confused.

Thea refused to talk to Roy due to him lying about what is going on with him. Later, she helped Sin to pick a dress for her "date" with the Starling Slasher, whom Roy later put in the hospital. Afterwards, Thea came to the hospital after Sin called her. Thea assured Roy she isn't judging him and is there for him if he needs her, which led Roy to break down and run away. Later at Verdant, a concerned Thea confided in Oliver about her issues with Roy keeping secrets from her.

Thea was delighted when Sara Lance was revealed to be alive and helped the latter prepare for her homecoming party at the Queen Mansion, where she introduced Sara to Roy and Sin. During the party, Thea sensed some tension between her brother and mother and tried to talk to Oliver about it, but he brushed her off. Thea hired Sara to be Verdant's bartender after Mandy quit. She later faked an emergency at the Queen Mansion in an effort to spur Oliver into resolving his issues with Moira.

When Slade Wilson, who donated to Moira's mayoral campaign, visited the mansion, Thea gave him a tour of the mansion's paintings.

Thea received a silver bracelet from Roy at Verdant, which she happily accepted. The day after at Verdant, Roy approached Thea and suddenly claimed that he wanted to break up with her, leaving her shocked and confused. Thea refused to accept this, knowing Roy was going through something and wanted to be there for him. Later, Thea went up the stairs and caught Roy making out with Becky, an employee, in a stockroom. Heartbroken and angered, Thea threw the bracelet he gifted her on the floor and stormed off. That evening, Thea tearfully told Oliver what happened and expressed her frustration at how everyone is lying to her. Thea embraced her brother, declaring he is the only one she can trust. While Thea was heading home, Slade's car stopped and he offered her a ride, which she accepted.

Thea was kidnapped by Slade but eventually released unharmed. However, Slade revealed to Thea that Malcolm Merlyn is her biological father, much to her shock and devastation. This revelation wrecks her relationship with Oliver and Moira.

A furious Thea stubbornly refuses to sign a form to protect the Queen family's assets from Isabel Rochev, claiming she is Malcolm's daughter and not Robert's. When Oliver tries to assure Thea that she is still his sister, Thea angrily retorts that she's irreparably damaged due to being the daughter of two mass murderers. Later, Thea decides to move out of the Queen Mansion, abandoning her family. In a last-ditch effort to get her to stay, Oliver reveals (having recently learned from Isabel) that Robert knew the whole time Thea wasn't his biological daughter, but accepted and loved her anyway. Although surprised, Thea ultimately doesn't change her mind. Thea knows her refusal to sign the form would likely bankrupt her family and leave those that work for them unemployed, but she is too focused on her own problems to care.

Thea continued to keep her distance from her family, even trying to prevent her mother from doing her campaign rally at Verdant, only going through with it since she signed a contract. Later in the club, Thea was put under Diggle's protection by Oliver, much to her annoyance. They talked about family and Diggle advised Thea to give hers a second chance. Suddenly, the news broadcasted Roy attacking a police officer. Thea met up with Sin, who told her about Roy's incident. At Moira's campaign rally, Thea gave a speech to lure Roy to Verdant, which worked. As Roy attacked the event, Thea attempted to get though him, to no avail. Roy attacked and nearly strangled Thea, but she was saved by the Canary and the Arrow, who promised her they would help Roy. Afterwards, Thea agreed to stay at the Queen Mansion for the night. As she and her family talked on the way home, Moira expressed how the family needed to start over and was about to tell her children something about Malcolm. Suddenly, their limo got crashed into, knocking the three of them out. Oliver woke up at the sight of Moira and Thea tied up, with Slade forcing him to choose between the two. When Slade was about to kill Thea, Moira stood up and offered herself instead. Thea pleaded for her mother not to, but Moira simply expressed her last words to her daughter: "Thea, I love you. Close your eyes, baby". Slade stabbed and killed Moira with a sword, while Thea helplessly screamed in horror and despair. Slade then left after untying Thea, who rushed to her mother's side and cried over her body as a heartbroken Oliver watched on.

Thea attended her mother's funeral and was visibly upset that Oliver was absent. Isabel later came to see Thea at Verdant, informing her that the club was built upon property owned by Queen Consolidated and she needed to vacate the premises. Afterwards, Thea told Oliver that she didn't want to give Isabel the satisfaction of kicking her out of her own home and needed a change of scenery. Oliver agreed and let her go. He bid farewell to Thea, stating she was always the best of their parents. Thea packed her things in a backpack, took one more look around her home and, ignoring a call from Walter, she left. Just as she was about to board the train, one of Slade's soldiers attacked the station.

Thea attempted to flee but was saved by her biological father, Malcolm Merlyn. Malcolm tried to talk to her but Thea ran off, wanting nothing to do with him. They were both attacked, but Malcolm was able to subdue the Mirakuru soldier. Thea grabbed a gun off the ground near a dead cop and shot Malcolm thrice as he tried to reason with her. Malcolm was shown to still be alive and reiterated that he needed Thea by his side, going as far as to compare her qualities to everything Tommy lacked. Thea left and reunited with Roy. Deciding to help Team Arrow during the Siege, Roy told Thea to stay at his house and pack her things, and they could leave the city together once he returned. However while packing, Thea discovered Roy's quiver of arrows and realized he was secretly the Arrow's sidekick, which he had kept from her all along. Betrayed once again, she ultimately decided to start her life over. Leaving a goodbye note to Roy, Thea decided to go with Malcolm and leave Starling City behind, with no intentions of coming back.

Training with Malcolm Merlyn
When Malcolm brought Thea to Corto Maltese, he began to train her, teaching her concepts such as "Pain is inevitable, but suffering is optional" by pouring boiling water over her hand. Thea attempted to resist the pain but soon placed her hand in the bowl of cool water below. Malcolm then decided to train her the same way he was trained. Thea was then beaten and kicked by Malcolm several times, before she pulled a sword on her father, to which he stated they could begin.

Five months later on October 8, Malcolm drugged Thea with Vitura, which made her highly susceptible to suggestion. The two of them traveled on a plane back to Starling City, where Malcolm ordered Thea to kill Sara. Thea ambushed Sara on top a building, calling out to her using a voice modulator. While Sara was thrown off by her presence, Thea successively shot her in the chest with three arrows, with the momentum causing Sara to fall to her death. Thea then returned to Corto Maltese with Malcolm and after the drug wore off, she retained no memory of this event. Over the next few days, Thea trained further, impressing Malcolm after beating two trainers. Thea proudly addressed him as "Dad".

While working at a café in Corto Maltese, Thea received a surprise visit from Oliver. She wondered how Oliver found her and later apologized for lying about her whereabouts, explaining that she just needed space. Thea soon realized that Oliver was there to convince her to go home but quickly shot him down. Thea then was visited by Roy, who apologized to her for all the lies he had told. When Roy asked if she felt lonely in Corto Maltese, Thea claimed that was the best part, as no one knew her or could lie to her. Later, Thea received another visit from Oliver, who decided to tell her the truth about their father's death: Oliver revealed that Robert made it to a life boat with him after the Queen's Gambit went down, eventually sacrificing himself when they ran out of resources. Oliver asked Thea to reconsider her decision on staying in Corto Maltese. Thea then requested to her father to go back to Starling City, but Malcolm believed that she hadn't gone as far as he'd thought. They had a duel in which Thea was disarmed, but she quickly disarmed her father in return, therefore proving that she was ready to leave. At the airport, a tourist accidentally spilled hot coffee on Thea hand, but she hardly flinched, much to Oliver's surprise.

Returning to Starling City
Thea had dinner with Oliver and informed him about her plans of reopening Verdant with the help of investors. Roy approached her later, asking if he could help, to which Thea sarcastically asked which shade of green he liked best. As she left the club with Roy, Nyssa confronted them and hit Roy with a tranquilizer dart when he tried to protect Thea. Thea then allowed Nyssa to kidnap her to save Roy. Nyssa kept Thea tied up and suspended upside down in an abandoned warehouse, intending to use her as bait to lure Malcolm to his death. However, Thea was rescued by the Arrow. Afterwards, she thanked Roy for trying to help her, hiring him as the assistant manager of Verdant. Malcolm called to check up on her and Thea thanked him for taking care of her. Malcolm stated that he had promised he would never let anyone hurt her.

Upon gaining access to Malcolm's assets, Thea used his estate money to buy a loft and the deeds to the Queen Industrial Inc. building to reopen Verdant. Oliver was furious upon learning this and realized Thea had no investors for the club. Oliver urged her to not use the money, pointing out Malcolm's past evil deeds, including Tommy's death. Upset, Thea proceeded to tell Oliver that the movers were coming to the loft tomorrow, so he could stop by with popcorn or not come at all. Later after Brother Eye's cyber attacks on the city, Thea met Oliver at Verdant. She stated that the two of them are family and requested that Oliver meet her halfway in their new relationship. The following day, Oliver arrived with popcorn and Thea invited him to live with her, which he accepted. Thea promised to donate the rest of Malcolm's fortune to charity once Verdant began turning a profit. The two then watched a movie and shared the popcorn.

While reopening her club, Thea held auditions for Verdant's DJ. A man named Chase arrived and told the other contesters to go home, as he is certain he is the right man for the job. Thea told Chase he can audition like everyone else, after which he left. During the grand reopening of Verdant, Carrie Cutter walked past Thea while she was disappointed by the performance of the DJ. Thea told him to leave and tried to use her playlist to provide the music when Chase offered to help her. After some negotiation, he started the music and the crowd began to dance, to Thea's pleasant surprise. During the party, Thea made Carrie a Cupid's Kiss. After the night was over, Thea and Chase shared a kiss and he let her keep his cut as a gift for her grand reopening.

Thea later walked down the street, telling Chase over the phone that their kiss didn't mean anything, but was distracted by a bolt of lightning moving past her. The next night at Verdant, Thea served drinks to Roy, Felicity, and their friends, Cisco Ramon and Caitlin Snow. Cisco expressed an interest in Thea but quickly moved on after learning she was Roy's ex-girlfriend and Oliver's sister.

Thea left flowers at Moira's grave and saw Laurel talking to Sara's grave. When Thea wondered why she was here, an emotional Laurel revealed that Sara was involved with some dangerous people and had been murdered, much to Thea's shock. Laurel made Thea promise not to tell Quentin about it. At her loft, Thea bought in an enormous Christmas tree, justifying to Oliver that the smaller the family, the bigger the tree. Oliver revealed he knew Malcolm was with her at Corto Maltese. Thea avoided the subject and proclaimed that Malcolm is one of the few family members she has left. Oliver asked if she flew from Corto Maltese with Malcolm. Thea maintained she did not and asks Oliver to not make her choose between her father and him. Later, Thea was decorating the Christmas tree when the Arrow broke through her window. He demanded to know where Malcolm was. Thea feigned being scared before throwing broken glass in his face. She then kicked the Arrow in the groin and threw multiple blows at him, though he dodged and parried the hits, forcing her to distance herself. Thea ordered the Arrow to stay away from her and her father before escaping by jumping off the balcony. Thea then contacted Malcolm and told him that the Arrow confronted her. Afterwards, Thea lied to Oliver and told him the window was broken by a bird. Oliver tried to warn Thea that she did not know who Malcolm really was and he did not love her because he was incapable of it (having learned he made Thea kill Sara), but Thea remained stubborn. Oliver replied that he was not going to make her choose; there was nothing he would not do to protect her. Confused, Thea hugged Oliver before he left, unaware of his impending duel with Ra's al Ghul.

Several days later, Thea continued her training with Malcolm, who taught her to adapt to her situation and her opponent's. She expressed her worries about Oliver's disappearance and Malcolm assured her he would look into it. Later, Thea returned home from work and found Malcolm waiting for her. He told Thea the city had become dangerous for them, and they must leave.

Thea met Chase at Verdant, where he asked her if they were good as he started to think she was avoiding him. Thea claimed they were good but held him off when he talked about their shared kiss. Malcolm later showed up in his car and said he expected Thea to pack and that they had to leave. When Thea wanted to know why, Malcolm simply stated she is not ready for the reason, to which Thea replied that she isn't willing to leave the city with him.

At her loft, Malcolm showed up and apologized for what he said. Malcolm explained that sharing the truth is sometimes difficult and revealed Ra's, whom he fell in with after the death of his wife, Rebecca, wanted to kill him and his family as revenge for the Undertaking.

Thea and Malcolm later spoke again at the loft. Thea still refused to leave the city, pointing out that Ra's will try to find and kill them anyway. Thea stated that Malcolm taught her not to be afraid and stand her ground, so she will not give an inch in battle as Ra's should be afraid of them. Moved, Malcolm agreed with Thea's decision to stay.

When Thea was flirting with Chase, Oliver came to talk to her. He explained he needed to show her something and took her into the Arrowcave, revealing his identity as the Arrow. While initially upset at all of the times Oliver was lying and being a "flake", Thea ultimately realized that her brother was protecting and saving people. She not only accepted Oliver's life, but praised him for it. Oliver then addressed the fact that Malcolm knew of his dual identity and they need to fight Ra's. Thea became angry at her father for manipulating Oliver.

After a failed attempt to find Werner Zytle, Oliver returned home and explained to Thea that despite his hatred for Malcolm, they needed him to take on Ra's, but she believed they could defeat him alone. Back at the club, Thea and Roy, who was pleased by Thea knowing about their lives, talked about Malcolm's involvement and Thea stated she prefers to keep her father out of their lives.

When Laurel was poisoned with an overdose of Vertigo, Thea came to the Arrowcave and saw the situation, realizing Laurel was Black Canary. Oliver sternly ordered her to leave. Outside the club, Thea met up with Chase and they slept together in her loft. When Chase poured them wine, Thea noticed an odd smell in the wine and revealed she learned that red wine was effective in covering the scent of cyanide. She attacked Chase with a cheese knife, but he effortlessly disarmed her and revealed himself as an agent of the League. Chase tried to slit Thea's throat but Roy saved her. Malcolm arrived and ambushed Chase, who killed himself when he had no way out.

After Oliver defeated Zytle, he came to comfort Thea. While she never asked to be a part of this, Thea agreed to let Malcolm help, but won't forget who he is or what he has done. Before Thea left the city with Oliver to train, she discussed her new normal with Roy and kissed him as thanks for saving her life. Oliver and Thea later arrived on Lian Yu.

While training on Lian Yu, Oliver learned that Malcolm released Slade from his A.R.G.U.S. prison, much to Thea's shock. The two went to retrieve some firearms from Robert's gravesite. Unfortunately, Slade ambushed the two, knocking them out and imprisoning them in his cell. Thea revealed to Oliver she knows he's keeping a secret from her and demanded to know what was going on. Oliver discovered a way to escape by dislocating Thea's shoulder, allowing her to extend her arm and open the prison door. After they escaped, Oliver eventually revealed to Thea that she was drugged by Malcolm into killing Sara. Horrified, Thea struggled to grapple with the truth, realizing Oliver was right about Malcolm all along. Slade suddenly held her at gunpoint, but Thea disarmed him. The three of them fought until Thea managed to wound Slade with a gunshot. She considered finishing him off but Oliver talked her out of it, urging her not to become a killer like Malcolm wanted. After some hesitation, Thea ultimately knocked Slade out with the gun, allowing them to imprison him back in the cell. The two returned home, where Thea angrily confronted Malcolm over making her kill Sara and betraying her trust. Thea proclaimed she will train, fight, and work with Malcolm, but he is no longer her father.

Thea and Oliver continued to train with Malcolm. She still struggled with the guilt over killing Sara and eventually revealed the truth to Laurel. Although shocked, Laurel assured Thea that it isn't her fault, but wondered why she would be associated with someone like Malcolm. Thea explained the situation, regarding the League coming after Malcolm, Oliver, and herself. Thea then contacted the League and made a deal to hand her father over to them. That night, Nyssa and the League showed up and manage to capture Malcolm while he was fighting with Laurel. Thea then informed Oliver about what she did back at her loft. Despite her protests, Oliver and Diggle left for Nanda Parbat to rescue Malcolm in order to stop Thea from losing her humanity once she realizes that she has sentenced her father to his death. Despondent, Thea went to the Arrowcave and met with Nyssa (whom Oliver manage to capture earlier), telling her the truth about Sara's death. Thea offered Nyssa a chance at revenge for Sara's death as she unlocked the latter's cell door and handed Nyssa back her sword.

Nyssa initially refused to believe Thea's confession, but Thea informed her in more detail about Sara's death, explaining that Malcolm drugged and brainwashed her with Vitura and how she shot three arrows into Sara's chest. Nyssa told Thea that there would be no justice in killing her and that this would all end with Malcolm's death. Suddenly, Roy and Laurel entered and attacked Nyssa (believing that she somehow escaped and was attacking Thea), but she subdued them and left. Thea then went home to her loft and discovered that Oliver has returned from Nanda Parbat with Malcolm. Later on, Laurel came to visit and talk to Thea about the situation. Thea then confronted Malcolm, who was listening to their conversation. Malcolm revealed that he knows Thea is holding a knife, which surprised her. Malcolm ordered her to kill him, but Thea declined. Thea and Oliver discuss Malcolm, Moira, and their past. Later on, Thea visited Roy at his home and asked if she can stay with him for a while, to which Roy agreed. The two began to kiss.

Thea and Roy attended Diggle and Lyla Michaels' wedding together.

Post-sex, Thea and Roy discussed running away together. The two then spotted the news reporting a manhunt for the Arrow. Thea arrived at the Arrowcave and witnessed Oliver speak over the phone with an angry Quentin, who wanted Oliver to turn himself in. Oliver apologized to everyone for putting them in this position, but Thea placed the blame on Malcolm. Back at Verdant, Roy told Thea that while he shot the cops, part of him felt "relieved" that he might finally go to jail where he belongs. Oliver came in and apologized to Roy. Just then, the police broke down the doors and Oliver took off as they chased after him. They then discover that all of their assets have been frozen by Quentin so Oliver couldn't escape the city.

Thea visited Roy (who masqueraded as the Arrow), at Iron Heights Prison. She was worried about him, but Roy assured her that everything would be fine. Thea returned to her loft along with a commanding officer, who both ordered Quentin to back off as he and a squadron of officers searched her loft for evidence to prove that Oliver is really the Arrow. Quentin then got a call and is informed about the failed attack on Roy at the prison, which he then told Thea about, much to her worry. After Roy is supposedly killed in prison, Quentin went over to Thea's loft to inform her about the situation. Oliver later arrived and comforted Thea as she cried. Later, Thea wistfully looked at pictures of her and Roy on her phone as she drank wine. Suddenly, Ra's al Ghul appeared in the loft. Thea vowed that her brother was going to kill him, but Ra's corrected her, claiming that Oliver is going to beg him for mercy. Thea then threw a knife at Ra'd and tried to run towards the door, but he stopped her. A brief fight occurred as Thea tried to defend herself. Unfortunately, Ra's had the upper hand and smashed Thea through a glass table. He then stabbed Thea through the chest with his sword and whispered a prayer before leaving. Thea was left on the floor with her life hanging by a thread as she started to bleed out.

Oliver arrived at the apartment and immediately took Thea to the hospital, where her condition began deteriorating. Oliver, Malcolm, Diggle, and Felicity decided to bring Thea to Nanda Parbat, where she would be resurrected and healed by the Lazarus Pit in exchange for Oliver accepting Ra's offer. Thea's body was prepared by the Priestess and lowered into the pit. Seconds later, Thea jumped out and attempted to attack Oliver in a feral manner, but was subdued. When she woke up, Thea's memories were scattered as she had no memory of who Oliver was, looked to Malcolm for comfort, and asked about her mother. When Felicity's plan to escape with Oliver fell flat, Oliver helped them by using his control over the other assassins. Oliver bid goodbye to his friends and Thea, asking her to never forget that he loves her. The next day, Thea woke up and regained her memory. As Malcolm recapped what happened, Thea was concerned about her brother.

Thea and Felicity had dinner with Diggle, Lyla, and their daughter, Sara. When Diggle wondered how she was doing after her resurrection, Thea assured him she was fine. Thea expressed that she misses Oliver and blames herself for his transformation. Thea later returned to the Arrowcave and talked to Felicity about her desire to help the team out on their mission. She then realized Oliver is back in town and wanted to talk to him, but Felicity dissuaded her. Thea headed back to her loft and contacted Malcolm, who informed her that Oliver is hunting down Nyssa so he could kill her and have no rival as Ra's al Ghul's successor. He tried to convince Thea to not get involved but she protested and persuaded him to help her instead. Later, during a battle involving the exchange of Lyla and Nyssa, Thea shot Oliver in the wrist with an arrow as he attempted to kill Diggle. This enraged Oliver, but he spared Diggle's life and left with a captured Nyssa. Thea then returned to the Arrowcave with the rest of the team, who admitted they have probably lost Oliver to Ra's and must now reassemble their efforts without him. That night, Felicity came over to Thea's home and talked to her about Oliver, with both women admitting they still love him. Felicity told Thea that they must move on with their lives and revealed to her about Roy being alive, as well as the fact that they staged his death. Felicity gave Thea a paper with his location and whereabouts, stating that she has an opportunity to start a new life with Roy if she wished.

Thea packed and headed to Monument Point to visit Roy. She brought him his Arsenal suit, explaining she had her father steal it out of impound. The two spent the night together at Roy's new home. Later, Thea explained what had happened after Roy left and how Oliver sacrificed his soul for hers. Roy informed Thea that he can't stay in Monument Point forever and will have to move again before someone figures out his identity. The following morning, Thea found herself alone in bed. She went to the auto-shop Roy worked at, only to learn he had quit. One of the mechanics gave Thea a letter and package meant for her. In the letter, Roy urged Thea to live the life which Oliver had sacrificed himself for and not one on the run with him, as he loved her too much for that. Thea then found out Roy had bequeathed her his Arsenal suit, stating that red always looked better on her.

Thea returned to Starling City in time to face the threat of Ra's al Ghul's bio-weapon attack, where she donned Roy's suit and arrived in time to save Diggle from a League member. Diggle interrogated the assassin for the Alpha-Omega's location, only to discover he was carrying the toxin in his blood and released it by slitting his own throat. Diggle insisted Thea leave but she assured him that Malcolm had already inoculated her. The two worked together to evacuate as many people as they could to save them from the virus and took down the fourth assassin before he could release it. This bought enough time for Oliver to kill Ra's and Ray to release the vaccine, curing everyone who'd been exposed. Team Arrow returned to Palmer Technologies, where Oliver commended the efforts of everyone present and declared his intention to retire from vigilantism, acknowledging that the city is in capable hands. At her loft, Malcolm informed Thea that he intended to leave Starling as well and tried to justify that regardless of everything he did, he will always love her and be there if she needs him. Though Thea is uninterested in his offer, she acknowledged the promise Malcolm made to make her stronger and thanked him for it. Thea later tried to convince Oliver not to leave the city, with no luck. Before he left, Thea asked if Oliver has a codename for her, suggesting "Red Arrow", but Oliver had already told everyone to call her "Speedy". Annoyed but humored, Thea bid farewell to Oliver as he left with Felicity.

Working with Team Arrow
After Oliver and Felicity left, Thea moved in with Laurel at the latter's apartment since she was haunted over almost being killed by Ra's in her home, but still kept the loft in her name. Over the next few months, Thea, Diggle and Laurel worked to keep the city, rebranded "Star City" in Ray's memory, safe. Eventually, a new terrorist group coined "The Ghosts" begun a series of attacks across the city, beginning with robbing banks and jewelry stores and escalating into stealing munitions and technology. The Ghosts proved to be a match for Team Arrow and would commit suicide using cyanide pills if captured.

In October 2015 during a siege of a Kord Industries weapons truck, Speedy and Black Canary moved in to intercept, where Speedy fought against a few men. One of the Ghosts pinned her down, but Diggle saved her before Black Canary blew up the truck wheels. However, the Ghosts had brought backup and escaped with their cargo. At the Arrowcave, the team discussed the hijacking, with Laurel and Thea agreeing that they were outmatched and needed Oliver's help, against Diggle's wishes. The next day, the city's leadership committee was targeted by the Ghosts' organization through various means of assassination. Thea failed in attempting to save one of them. Thea and Laurel then traveled to Ivy Town, where they revealed to Oliver and Felicity of the Ghosts and how they were outmatched. Oliver reluctantly agreed to return to Star City until the new threat was dealt with. Eventually, Team Arrow found the Ghosts and observed as their leader addressed his men and killed one of them for failing to deal with the vigilantes. He then killed some other Ghosts by simply touching him. As Team Arrow attacked, Speedy engaged one of the Ghosts but became unhinged and repeatedly punched him, almost stabbing him with her sword until Oliver stopped her. As Oliver and Thea searched for the bomb the Ghosts intended to use on the new railway line, Oliver addressed her outburst but she tried to assure him she was fine. At the opening of the railway line, Speedy evacuated the civilians as Team Arrow worked to defuse the bomb. After succeeding, Thea was present as Oliver revealed the Ghosts' leader to be Damien Darhk, Ra's al Ghul's most bitter enemy, but was confused since Damien had already left Star City months ago. Thea later witnessed Oliver broadcast a statement to Star City, declaring his intention to protect it as "Green Arrow".

Thea helped the team try to prevent another Ghost attack. Later, Oliver and Thea had brunch at the loft with their mother's old friend, Jessica Danforth, and her daughter, Madison Danforth. Jessica told them of her plan to run for mayor. At Jessica's mayoral announcement, Oliver and Thea protected her from Lonnie Machin, a man hired by Damien Darhk to kill Jessica. When Thea tried to torture a drug dealer to get information on Machin, Oliver sent her away. Oliver later called Thea out over her recklessness, ordering his sister to not be so aggressive when she's out in the field. Thea suddenly mindlessly attacked him until Laurel and Diggle subdued her. Oliver then revealed that Malcolm had warned him about Thea's resurrection changing her, which he was initially unconcerned about since she appeared to be fine. Thea later explained to Laurel that Oliver revived her using the Lazarus Pit in Nanda Parbat when Ra's al Ghul fatally stabbed her. After the team were able to locate Machin and rescue a kidnapped Madison, Thea went too far and set Lonnie on fire in a fit of rage, much to her horror. At Laurel's apartment, Oliver apologized to Thea for not telling her about her bloodlust sooner and assured her that they will deal with this together. Laurel offered to take Thea out of town for a spa weekend to clear her head, which Oliver agreed to. However, Laurel told Thea in secret that they were actually going to Nanda Parbat to resurrect Sara.

When Laurel and Thea arrived in Nanda Parbat, Malcolm refused to resurrect Sara as the Pit had never been used to bring a person back from the dead. Thea confided in Malcolm about the bloodlust she experienced recently and asked for his help. Malcolm claimed there was a sage on a nearby mountain who could help her. That night, Thea was awoken by two assassins breaking into her room, whom she killed. Malcolm revealed that the only way to for Thea to get rid of the bloodlust was to kill the one who originally hurt her, which was impossible since Ra's was dead. Thus, Thea could only periodically satiate the bloodlust by killing. Later, Malcolm agreed to use the pit on Sara and Thea witnessed her coming back to life.

When Thea and Laurel returned to Star City, Thea agreed not to tell Oliver about their experience in Nanda Parbat. Thea joined the rest of the team when Oliver announced to them that he intended to run for mayor and then went down to the new and improved Arrowcave, which was underneath Oliver's campaign office. When the team needed to draw out a team of cops from the Rogue Anti-Vigilante Task Force, Thea got in touch with her old drug dealer to buy $74,000 of cocaine. However, the cops stole the drug shipment and escaped. After the task force kidnapped Quentin, Thea aided the team in preventing the cops from stealing weapons within the SCPD. Afterwards, Thea used her connections to hire a team of interns for Oliver's mayoral campaign. She wrote a speech for her brother's mayoral announcement and witnessed him give it.

The resurrected Sara escaped and began to attack women who bore striking resemblances to Thea. Sara later attacked Thea at Laurel's apartment, but Thea managed to fend her off and escape, albeit injured in the altercation. At the hospital, Thea sadly revealed to Oliver and Felicity that Sara was suffering from the side-effects of the Lazarus Pit and confessed Malcolm had her kill two League members to quench her bloodlust. Thea expressed her belief that maybe Sara would be at peace if she killed the former. Later, Thea sensed Sara's arrival at her hospital room. Initially accepting the inevitable, Thea explained she understood why Sara wanted to kill her and assured the latter it was okay. Sara then began choking her but Laurel and Oliver, who were keeping watch outside, intervened. Later after Thea got out of the hospital, she learned of her mental connection with Sara due to the Pit and offered herself up as bait to lure Sara to them, which worked. After John Constantine, an old friend of Oliver's, helped to return Sara's soul to her body, Oliver and Thea made amends as Oliver assured her that he was in no position to be angry with her for keeping secrets.

Alex went over their campaign itinerary with Thea and Oliver. When Oliver left, Alex asked Thea out on a date which she rejected, citing her already complicated life. Thea later helped Team Arrow in stealing a quantum manifold from Kord Industries and regrouped with them when they discovered Ray being held captive in the Latin Building by Darhk. While the rest of the team recovered Ray, Thea, Laurel, and Sara attacked the Ghosts head-on, but they witnessed Sara kill one of them as a result of her bloodlust. Afterwards at Laurel's apartment, Sara decided to leave and find a way to cope with the bloodlust. They tried to convince her to stay but she insisted on figuring things out for herself. Accepting Sara's choice, Thea and Laurel bid her farewell. The next morning, Thea asked out Alex for some drinks later that night.

Thea accompanied the team in fighting off a Ghost attack on a Star City Bank armored truck. During the fight, Thea nearly killed a Ghost with her sword, but managed to stop herself. However, the Ghosts were successful in burning the money. The team later broke into Wolfman Biologics. Malcolm then visited Thea since he knew Thea's bloodlust was returning. He gave her a file on a pedophile who lived three blocks away that he wanted her to kill. Thea angrily refused and left. Thea's relationship with Alex grew as she took the first step towards their date. After participating on a mission to rescue Ray Palmer from H.I.V.E, Thea's blood-lust returned and affected her during dinner with Alex. When she encountered Damien Darhk in the fight to save Andy Diggle, Darhk tried to suck the life-force out of her, but his powers failed against her. Later, Thea asked Malcolm to use that as an advantage.

Thea was present at Oliver's cleanup of Star City Bay, where a drone opened fire on the crowd. Thea later supported Oliver's plan to expose Damien Darhk's identity to the public. Malcolm later paid a visit to Thea, informing her that Damien's powers that mitigated her bloodlust were not related to waters from the Lazarus Pit. Thea was later kidnapped by Damien at Oliver's mayoral holiday party and put into a gas chamber along with Diggle and Felicity. Laurel and Malcolm (dressed as the Green Arrow) arrived and broke them out of the gas chamber. Later that night, Thea happily watched on as her brother proposed to Felicity.

Thea delivered flowers from Oliver to Felicity before her surgery. She later talked to Laurel about her concern regarding Machin's return and her regret for burning his face in a bloodlust-driven rage. They then walked in on Quentin and Donna and realized the two were dating. Thea took Donna to the cafeteria to give Quentin and Laurel some space to talk. Team Arrow tracked Machin to his foster parents' house, but he rigged a motion sensor gunfire trap. Thea escaped and pursued Machin, holding him at arrow point. However, the rest of the team intervened and took him into custody. Thea later interrupted Oliver's interrogation of Machin in an abandoned warehouse to inform him that Felicity was out of surgery. Thea then started questing Machin, who began taunting her. As Thea started threatening him, Machin tried to goad her into killing him. Thea held an arrow to his throat and started drawing blood but the police arrived, forcing her to flee. Feeling like she was losing control of herself, Thea went to see Alex and break up with him. However, Alex reminded Thea of her resilience in face of multiple tragedies, affirming that she was strong enough to get through her issues. The team later found Machin at Darhk's home. Thea and Oliver battled Machin while Laurel and John got Darhk's wife and daughter out safely. Thea caught up with Machin in the forest and used a trick arrow to tie him to a tree. However, she hesitated in killing him, allowing Machin to cut himself free with a hidden knife and escape once again. After the mission, Thea invited Alex over for wine and they kissed.

When Diggle and Lyla were ambushed by armed attackers, Team Arrow helped them track down the culprit, Shadowspire, who had kidnapped two A.R.G.U.S. operatives. The team tracked them to Pacific Freeport, but found the two agents already dead. They later monitored Shadowspire's next target: a shipment of railguns from Kord Industries. However, the railguns were a ruse and Shadowspire's real target was A.R.G.U.S. headquarters. Thea, Oliver, and Laurel burst into A.R.G.U.S. under Felicity's instructions and helped take down Shadowspire before they could access Rubicon.

Despite the potential asset of her immunity to Darhk's powers, after Thea's bloodlust reached a point where her body was starting to destroy itself because she wouldn't kill others, Oliver arranged for Nyssa to give Thea the cure after helping her regain control of the League of Assassins. Thea continued with the team after a brief reunion with Roy, but after she fell under Malcolm's influence again and threatened to kill Darhk's daughter after being released, Thea decided to leave the team as she didn't like what she was becoming.

Chief of Staff
Although she retired from life as a vigilante, Thea continued to help Oliver in a civilian capacity as his Chief of Staff (Oliver having been appointed Mayor after the death of Ruvé) and has proven herself to be an able politician, often picking up the slack for Oliver, who simultaneously worked as the Green Arrow. In October 2016 when Oliver was kidnapped by Tobias Church, Thea returned as Speedy to help rescue him. However, she grew furious upon seeing that Oliver was willing to kill beyond last resort in the wake of Laurel's death. They had an argument and Thea refused to return to the team. She hired Quentin Lance, who had been fired from the SCPD after revealing that he had previously collaborated with Damien Darhk, as the city's Deputy Mayor.

Thea temporarily came out of retirement as Speedy when the Dominators attacked Earth and accompanied Team Arrow to Central City, where she met Kara Danvers/Supergirl from Earth-38. Thea was briefly brainwashed by the Dominators but later freed by Barry. Shortly after, Thea, Oliver, John, Sara, and Ray were beamed onto the Dominators' mothership. Thea was placed into a computer-simulated reality where her parents, Tommy, and Laurel were all alive, Oliver was getting married to Laurel, and she was the owner of Verdant. Thea eventually realized this reality was fake when she experienced visions from the real world, including her mother's death, but wanted to stay, despite Oliver and Sara's protests. Thea pointed out that they finally have a chance to be happy and she didn't want to lose her family again. Though saddened, Oliver accepted this and left. At the last minute though, Thea changed her mind and helped Oliver and her friends battle visions of their enemies, personally defeating a vision of Malcolm. Thea watched on as Oliver and Sara bid goodbye to Laurel before the group left the reality through a portal in Smoak Technologies. The five of them were able to escape from the mothership and were rescued by the Waverider. After this ordeal, Oliver arranged for Thea to be dropped off back in Star City.

After Oliver's near-impeachment, Thea decided to resign as his Chief of Staff, fearing that she was relying too heavily on dirty politics, including tarnishing a reporter's reputation and considering blackmailing a city council member for his vote.

Thea, along with the rest of Team Arrow, was captured by Adrian Chase and taken to Lian Yu. After stepping on a landmine, Thea was pushed off of it by her father, who had joined forces with Oliver to rescue her; he later detonated the landmine to take out Digger Harkness and some of Chase's henchmen, leaving Thea devastated over the loss of a man whom she hates but comes to terms that while Merlyn was not a good father or person, he proved that he loved Thea.

Comatose and return
During the destruction of the island, Thea was rendered comatose. Five months later, she was on life support at Starling General Hospital. Thea finally awoke from her coma on Thanksgiving, much to Oliver's joy. She had a mini Thanksgiving dinner with Oliver, Felicity, Diggle and William and began to get to know her nephew. Thea attended Oliver and Felicity's wedding celebration in which she remarked about how nobody but Diggle had been invited. Afterwards Quentin Lance took her back to her apartment only to discover Black Siren. Black Siren knocked out Thea and Quentin, kidnapping the latter and leaving a phone on the former. Thea delivered the phone to Oliver and later talked with Oliver about Rene Ramirez's betrayal.

After Quentin fired Rene as Oliver's Chief of Staff, he rehired Thea to fill the position.

Rewritten reality
In an alternate reality created by the Legion of Doom with the Spear of Destiny, Malcolm had it so Thea adored him as a father and was part of his family, along with Rebecca and Tommy. It was implied that Thea was the biological daughter of Malcolm and Rebecca in this reality.

Personality
Initially, Thea was an arrogant, reckless, selfish, impulsive and immature spoiled brat. She turned to a life of substance abuse and partying to fill the void of losing her father Robert and older brother Oliver Queen. However, when Moira tried to be a decent parent for the first time by grounding her for breaking into a store, Thea obeyed the punishment even though she called Moira out at first. She also has a good heart and often tries to do the right thing, and looks up to Oliver. When she meets Roy Harper, a young criminal, she quickly forms a strong romantic attraction, and she is shown to be extremely devoted to him, repeatedly bailing him out of jail. She also showed up to the auction for Unidac Industries to support Walter even though she said she had no intention of going at first. After Roy is saved by the Hood, Thea goes along with him to meet the man who saved his life. This shows that Thea, while young, reckless, and impulsive, has a strong sense of loyalty and camaraderie for those she loves. Thea is also shown to be unpredictable. One example was when she would intentionally show up late to school and sometimes be on time.
 * -|As a civilian=

After working with Laurel, her partying and drug abusing days came to be exchanged for a more dutiful and emotionally responsible personality. After the quake, Thea became much more responsible, having to fend for herself financially from Moira's imprisonment, and Oliver's self-imposed exile. She eventually became the new owner of Verdant. In Season 2, though Thea was originally opposed to Roy being a vigilante like the Arrow she eventually warmed up to it when Roy saved Sin, although Thea still tried to be involved as much as possible. When Roy is injected with the Mirakuru and becomes more aggressive, Thea begins to feel pushed away as Roy doesn't talk about it with her. When Roy later breaks up with her she becomes extremely depressed. Furthermore, when Thea learns that Malcolm Merlyn is her biological father from Slade Wilson, she becomes angry towards Oliver and Moira, for keeping the secret from her, branding them liars and disowning them as family. When Moira was murdered by Slade to protect Thea, right in front of her with her final words to Thea that she loves her, Thea is completely devastated, numb with despair to the point she decides to leave Star City.

When Malcolm appears during the Siege, protecting her from Slade's super-soldiers, saying he was her father, she at first rejected Malcolm, was disgusted by him and even tried to shoot him, (Thea is more like her biological father, then she realizes). However, after Thea learned of Roy working with the Arrow, this was the last straw for her and so she went back to Malcolm. Determined not to feel weak or hurt ever again, Thea sought training from Malcolm, to teach her how to defend herself.

After six months' training under Malcolm, Thea has become a much more confident, disciplined, emotionally stronger person and can physically fend for herself as well. Despite Malcolm being a murderer, she has accepted Malcolm as her father and calls him "dad". However, she has also become manipulative in lying about not knowing Malcolm, his training her and avoiding any conversations about him with Oliver. Malcolm's harsh training has turned her in a capable fighter as she is able to act quickly and decisively when cornered. This was shown when confronted with the Arrow, she threw glass in his face and kicked him in the groin after which she escaped. Later on, when Thea finally learns of Oliver's identity as the Arrow, she showed great maturity in accepting her half-brother's vigilante identity, she went back to looking up to him and gracefully praised him for all of the lives he'd saved, for all the good he'd done for Starling City, knowing everything he did was to protect her.

However, when Thea learns from Oliver that Malcolm had drugged and brainwashed her with Vitura (a drug that made her extremely susceptible to suggestion) and had her murder Sara Lance under his manipulations, Thea is devastated. She is beyond horrified at what she was forced to do. She begins to unravel, holding Slade Wilson at gunpoint on Lian Yu, and viciously turns against Malcolm. When faced against the League of Assassins, Thea arranges for them to kidnap Malcolm so he faces justice. When Oliver points out, she will feel guilty for what she did, she tried to brush this off, however, her conscience catches up with her, Thea realizes she tried to have her own father killed while wracked with guilt over Sara and coming to regret every decision she's made since accepting Malcolm. She even attempts suicide by Nyssa's hand. When Oliver returns with Malcolm, Thea, feels remorse for what she did to her father, but covered it up, when she said she would turn him over to the league all over again. She laments she doesn't know what she's doing, who she is anymore.

After being revived by the Lazarus Pit (after she was nearly killed by Ra's al Ghul), her rebirth appeared to have left its mark on her soul. She had a much more actionable persona as well as a dark sense of honor. She feels responsible for her half-brother's defection for his joining the League of Assassins. When Oliver was supposedly brainwashed and had John at sword-point, she shoots an arrow through her half-brother's arm to stop him and threatened him the next would be in his eye. When Roy decides to end their relationship, as well as leaving her his Arsenal suit, she accepts it and is inspired to assume her own mantle joining Team Arrow and operate as a vigilante under the name Speedy.
 * -|As Speedy=

After six months of being a vigilante, the side effects of the Lazarus Pit's waters started to take affect, Thea has become extremely aggressive and bloodthirsty to the point of being unstable and unpredictable. Although she was later cured of this condition.

Thea's integrity comes grealty into question as she exhibits traits more and more like that of her father, this was clear in her hypocritical criticizm of Malcolm putting an innocent child's (her nephew William) life in danger when she did exactly the same thing when threatening the life of Nora Darhk, although her motive was to stop the latter's father, Damien Darhk from killing Oliver, Thea still had no right to threatened the life of an innocent child - this awakened her to the notion that she is more like her father than she initially realized and so, after Damien's death, she retired from vigilantism and refused to return to Team Arrow.

Thea has lost her sense of morality, pushing reasonable boundaries; such as when she framed Susan Williams for plagiarism simply because of her dislike for the latter as a reporter or when she revealed that she had evidence to prove that her half-brother Oliver, is Green Arrow, a scheme which resulted not only in Susan losing her job, but her life and reputation being ruined, Thea tried to justify this act by the incentive of protecting her half-brother, only for Oliver to cruelly criticize Thea's actions, pointing out the similarity of her misguided choices to that of their late mother, Moira Queen.

As noted by Malcolm; Thea is short-sighted, as she is incapable of seeing the larger picture.

Former powers

 * Dark magic immunity: It has been revealed that Thea is immune to Damien Darhk's powers as when he tried to use his life-siphoning magic on her, it backfired onto Damien, almost killing him. This is most likely due to the Lazarus Pit and its magical properties, as well as Thea's bloodlust. However Thea has since been cured of the Lazarus Pit's effects, so she is likely no longer immune to Damien's powers.

Abilities

 * Peak of human physical condition: After five months of training from Malcolm Merlyn, Thea became a strong fighter, able to take on several opponents in battle. During her training, she showed remarkable flexibility and coordination. Thea is strong enough to easily break the arm of a grown man with one hand. During a battle against Lonnie Machin, Thea was able to block his baton strikes barehanded using her forearms with no discomfort.
 * Acrobatics/Free-running: After five months of training from Malcolm, Thea was able to escape from Oliver Queen (in his guise as the Arrow) by jumping off her balcony. As a vigilante, she is also able to easily perform parkour, scaling buildings and going from one tall point to the next.
 * Honed senses: Thea has sharp senses and an acute sense of danger. When brought to Tevat Noah by Alex Davis for a "vacation", she soon deduced something was wrong by picking up minute details in her surroundings.
 * High-level intellect/Great business acumen/Great political acumen/Skilled tactician: Thea has proven to be very savvy and intelligent, though not quite on an academic or scientific basis. Upon taking over Verdant, Thea became a successful businesswoman and was able to run the club perfectly despite not having any degree in the subject. She also had an aptitude for politics, efficiently helping to manage Oliver's mayoral campaign. As Oliver's chief of staff, Thea proved to be an excellent politician and often picked up the slack for her brother in his first few months. She is skilled in strategizing and planning, having helped Oliver and Felicity Smoak set up a fake wedding to lure out Cupid. Thea is also able to use her surroundings to her advantage when in battle, as shown when she triggered a booby trap to fend off a group of assassins of the Thanatos Guild.
 * Multilingual: Thea is capable of fluently speaking English, Spanish, and Arabic.
 * Expert investigator: Thea is a highly skilled investigator, able to trace a wallet chain to Roy Harper, who stole her purse at the time. She also utilized these skills as a vigilante, such as determining Cupid's victims using her knowledge of celebrity gossip. Thea can sense when someone is lying to or hiding something from her, as she figured out that Oliver and Moira Queen were secretly fighting, noticed that Oliver was keeping a secret about Sara Lance, and that something was bothering him during a mission in Central City.
 * Toxicology: After being trained by Malcolm, Thea became familiar with poisons, able to detect disguised cyanide in red wine.
 * Master hand-to-hand combatant/Martial artist: Thea was trained by Malcolm in Kenjutsu and martial arts, becoming a highly trained hand-to-hand combatant and could easily beat two trainers. She combines her sword expertise with powerful kicks and punches. When Oliver confronted her (in his guise as the Arrow), Thea landed a groin kick and then rapidly executed multiple strikes on him (though Oliver easily blocked and dodged her blows) before fleeing the scene. However, Thea was unable to fight off Chase, an agent of the League of Assassins, and would have been killed if not for Roy and Malcolm's intervention. Later on, Thea was able to fend off Slade Wilson alongside Oliver, though Oliver was seriously injured at the time and Thea would have been defeated if she had not pulled a gun on Slade. Unfortunately, Thea was no match for Ra's al Ghul, as she was easily overpowered and almost killed by the latter, proving that her combat skills are still not yet at her half-brother and father's level respectively. After a further five months of training, Thea could battle Ghosts with little assistance and fight evenly against Machin, even besting him on two occasions. After being in a coma for six months though, Thea became somewhat out of shape and was easily knocked out by Black Siren. However, after a few months of presumably training to regain her combat skills, Thea was able to roughly hold her own against Ricardo Diaz and Athena. Since then, Thea's skills have improved to the point of mastery; she held her own against Talia al Ghul, soon managing to surprise and wrap a chain around the latter's throat using a chokehold.
 * Master stick-fighter: Thea is highly skilled stick-fighter, often spared with Malcolm and Oliver using escrima sticks. In their final battle, Thea fought on par with Athena using her bow as a melee weapon, eventually disarming the latter.
 * Expert swordswoman: During the five months Thea spent with Malcolm, he trained her in many forms of sword fighting. Thea became so skillful that she could easily defeat two trainers at once and received praise from Malcolm during their sparring sessions. Thea was able to duel on par with Malcolm for a while on two occasions, even briefly pinning him down in one encounter, though Malcolm was clearly holding back and ultimately overpowered her both times. A few years later though, Thea's skills have greatly improved, allowing her to stand her ground against Athena, the leader of the Thanatos Guild, for a while in a sword fight.
 * Master knife wielder/Knife thrower: Without looking at him, Thea was able to throw a letter opener at Malcolm's forehead, which he caught. She repeated this feat against Ra's al Ghul, able to throw a knife straight at his head from across the room, though it was ineffective. Thea also proficiently wielded a cheese knife as a weapon in close combat whilst attacking Chase. She was later able to swiftly stab Athena in the chest with a dagger whilst the latter was briefly distracted.
 * Skilled markswoman: Thea was able to successively fire three shots at Malcolm at his chest in close-range, though he was wearing protection. Presumably after training with Malcolm, Thea is now more familiar with firearms and can easily handle them.
 * Expert archer: Thea is a highly proficient archer, having won multiple archery contests. After being trained by Malcolm, she was able to quickly shoot three arrows into Sara's chest and an arrow into Oliver's arm with great accuracy. After joining Team Arrow, Thea became an efficient archer in the field, able to shoot her targets even whilst in fast-moving vehicles.
 * Indomitable will/High tolerance for pain/Expert survivor: Thea was taught by Malcolm to withstand pain by having hot water poured over her hand. By the end of her five-month stay with him, she didn't even flinch when someone accidentally spilled hot coffee on her hand. When Oliver dislocated and relocated her shoulder, Thea merely groaned, showing she was able to tolerate this pain as well. Thea has also demonstrated great mental strength, able to overcome the brainwashing effects of H.I.V.E.'s drug with her brother's encouragement and regain her independence. While training on Lian Yu, Thea could survive its harsh conditions with Oliver.
 * Stealth: Thea was able to sneak up on Sara (albeit under the influence of Vitura), who only realized she was there when the former called her name.
 * Network: As a former member of the social elite, nightclub owner and politician, Thea has a wide array of contacts, which she used to hire interns for Oliver's mayoral campaign and put together a "Star City Nights" festival at the Rockets Arena.

Former weaknesses

 * Bloodlust: Since being revived by the Lazarus Pit, Thea was left with an insatiable bloodlust and the impulse only subsided for a month at a time if she gave in to it. The only way for Thea to permanently end it was to take out the one who killed her, which was impossible as Ra's al Ghul was already dead. When Thea resisted the urge, the bloodlust eventually turned on her and began to take her own life. Ultimately, Thea was saved when Nyssa al Ghul provided her with the Lotus elixir, which permanently cured her of the bloodlust.

Equipment

 * Arsenal suit: Thea was given Roy Harper's Arsenal suit when she visited him after learning Team Arrow had faked his death. She uses it as her heroic alter-ego, Speedy, to hide her identity from her enemies. It is unknown what materials the suit is made from, with the exception of Kevlar.
 * Customized recurve bow: While fighting crime as Speedy, Thea uses a red-colored recurve bow.
 * Customized hunting arrows: While killing Sara Lance, Thea used hunting arrows similar to that of Malcolm Merlyn and members of the League of Assassins. As Speedy, Thea uses red-colored arrows similar to Roy's.
 * Trick arrows: Thea carries a number of different trick arrows, two of which include a grappling hook and syringe arrow.
 * Quiver: While killing Sara, and as Speedy, Thea wears a dark quiver to carry her arrows with her.
 * Sword: Thea carried a double-edged sword strapped to her back, right next to her quiver. She used it in her sparring sessions with Malcolm and a fight against Athena.
 * Flechettes: Thea carries red flechette darts holstered on her right thigh.
 * Combat knife: Thea keeps a combat knife holstered in her boot, which she used to stab Athena.

Former equipment

 * Customized compound bow: While killing Sara and shooting Oliver Queen (as Al Sah-Him), Thea used a bow similar to the one Malcolm used.
 * Dark Archer suit: While killing Sara, Thea wore a dark suit with a hood.
 * Jian: Thea had a Chinese straight sword for her training with Malcolm.
 * Katana: Thea used a katana for training in Kenjutsu.
 * Shinai/Bokken: Thea used a wooden sword for training in Kenjutsu.

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Trivia

 * Even before becoming Speedy, Thea already had some skill in archery, as several archery trophies can be seen in her room. This concept recurs when she throws an empty bottle with great accuracy to save Roy Harper from a thug with a gun.
 * Thea enjoys shopping. Because of this, she is well-versed in fashion brands.
 * She loves Big Belly Burger, especially the french fries.
 * Thea took dressage lessons as a child.
 * She had an "obsession" with art in her senior year of high school.
 * She has many followers on social media.
 * Thea is an avid follower of celebrity gossip.
 * She likes the Harry Potter series.
 * When Thea found out her true parentage, she thought "Thea Merlyn" was amusing. Though she is still legally known as "Thea Queen", she has occasionally jokingly referred to herself with the "Merlyn" surname.
 * Thea suggested that her vigilante identity could be "Red Arrow", before being prompted by Oliver to take on the name "Speedy". In the comics, Red Arrow was an alias used by Roy Harper and Emiko Adachi.
 * As the daughter of a previous Ra's al Ghul, Thea is an heir to the demon like Nyssa.
 * It is also possible that as Malcolm's daughter, Thea may have some legal shares in Merlyn Global Group, assuming the company is still operational.
 * Thea has been kidnapped seven times in the series:
 * In, she was kidnapped by the Hoods in their pursuit of revenge for the Undertaking.
 * In, she was kidnapped by Slade Wilson in his vendetta against Oliver.
 * In ​, she was kidnapped by Nyssa as bait for her father, Malcolm.
 * In ​​​​, she was kidnapped by Damien Darhk alongside Felicity Smoak and John Diggle.
 * In ​, she was kidnapped by a brainwashed Alex Davis and brought to Tevat Noah on Malcolm's behest.
 * In ​​, she was kidnapped by the Dominators along with several of her team members and placed into a simulation.
 * In ​​​, she was kidnapped by Prometheus's team alongside Oliver's family and friends.
 * Thea has had four love interests in the series: Shane Colvin, Roy Harper, Chase, and Alex Davis. She also expressed an attraction towards John Constantine.
 * Additionally, Thea has caught the romantic interest of Cisco Ramon/Vibe and Rene Ramirez/Wild Dog, though she has firmly told Rene that he isn't her type.
 * Thea also had a brief crush on Tommy and drunkenly tried to kiss him, unaware of her relation to him at the time. She would later realize this after learning Malcolm is her father and feel disgusted by it.
 * Thea is technically the first character to successfully kill a member of Team Arrow, current or former when she killed Sara Lance (though she was brainwashed by Malcolm).
 * Thea is right-handed, as whenever she is seen using her bow and arrow, she always uses her right hand to pull back on the arrow.
 * In the Season 4 episode ​​​​, Thea quit being Speedy. However, she was forced to don the mantle again in  to rescue Oliver when he was kidnapped by Tobias Church. Thea did so again in ​ to fight the Dominators and to help Oliver find Prometheus, though these times were voluntary. She would put the hood back on to rescue Roy from Diaz.
 * Thea's middle name, Dearden, most likely comes from her mother's maiden name.
 * Thea is nine months and three days younger than her late Earth-2 counterpart, proving that doppelgängers do not necessarily share the same birth date.

Behind the scenes

 * In the DC comics, Mia Dearden was a teenage girl who was second to take on the mantle of Speedy (the alias of Green Arrow's sidekicks). The first Speedy was Roy Harper, who in the comics also happened to have a drug addiction problem like Thea. This is adapted on the show by having Oliver's nickname for Thea be "Speedy", which she later adopts as her vigilante name.
 * Even though Thea was initially thought to be an original character, as seasons progressed, more similarities were shown between her and the second Speedy, like her middle name being Dearden and using the name "Mia" during her time in Corto Maltese. Thea being an adaptation of Mia Dearden was all but confirmed when she finally joined Team Arrow under the codename Speedy, taking Roy's costume and his place like in the comics.
 * Willa Holland was only contracted for 14 episodes out of Season 5's 23. However, she appeared in 15 episodes.
 * Thea shares multiple similarities with Damian Wayne, the current Robin in the comics. Both Thea and Damian are the illegitimate children of vigilantes (Malcolm and Batman/Bruce Wayne). Thea and Damian also at one point were "heirs to the demon", as Malcolm was Ra's Al Ghul and Damian's grandfather is Ra's Al Ghul. They are also related to a chosen successor of Ra's (Oliver and Bruce). Both Thea and Damian are skilled sword fighters and carry swords while on patrol, and are also prone to fits of violent rage.
 * Even though Oliver was originally an only child in the comics, Thea's introduction in the series would inspire the introduction of Emiko "Emi" Queen, Oliver's half-sister in the New 52 Green Arrow comics starting with issue 18 of their first volume that was released around the end of Arrow's first season. Emiko would have a few similarities with Thea, including having been used as an assassin by their other parent (Shado and Malcolm Merlyn), whom they later turned against and fighting alongside their brother as part of his team.
 * Incidentally, Thea once considered "Red Arrow" as her codename, which Emiko would take up in the 15th issue of the Green Arrow series from the DC Rebirth event.
 * Emiko would appear in season 7 of Arrow and use the name "Green Arrow".
 * In the original pitch for, Thea's name was spelt as "Thia".