- "People need to be afraid! Even if it means we have to sell it to them!"
- —Mercy Graves[src]
Mercy Graves was a criminal, former Cadmus agent and Lex Luthor's former head of security at Luthor Corp. She is also the sister of Otis Graves and the ex-girlfriend/former friend of Lex. After Lex's arrest, Mercy and Otis went to work for his mother, Lillian Luthor, at Cadmus. Following Lillian's arrest and Cadmus' disbandment, Mercy and Otis helped Ben Lockwood/Agent Liberty found the Children of Liberty, backed, in secret, by Lex Luthor. Mercy was later killed by a Hellgrammite as revenge for his capturing and brainwashing.
In 1996, Mercy Graves and her family went on a vacation to an unknown destination. During this time, Mercy somehow caused dangerous harm to her brother, Otis, to the point that paramedics were called in an attempt to resuscitate him.
Working at Luthor Corp
At some point, Mercy became acquainted with the Luthor family and began working as Lex Luthor's head of security at Luthor Corp. Their relationship grew overtime until Mercy became Lex's closest confidant and the two soon began dating. Mercy was also close to Lex’s younger sister, Lena Luthor; she took Lena under her wing, becoming a big sister figure and mentor to the young girl, and even personally taught her how to shoot a gun.
Mercy eventually grew frustrated with Lex’s hyper-focus on Superman instead of looking at the bigger picture, which soon ended their relationship. Feeling that intelligence wasn't enough and humans needed to find a way to match the superhuman abilities aliens possessed, Mercy left Luthor Corp.
When Lex was arrested, Mercy betrayed him by becoming a state's witness in his trial and helped put Lex behind bars.
After Lex's incarceration, Mercy and Otis became associated with his mother, Lillian Luthor, and worked for her at Project Cadmus. However, Lillian was also later arrested by Supergirl, which caused Cadmus to be shut down.
Working with Agent Liberty
Sometime after Cadmus' disbandment, Mercy and Otis sought to continue their anti-alien vendetta on their own. Backed by an unknown entity, the duo tried to find a way to unite those who shared their views into an organization to wipe out all extraterrestrial life on Earth and establish humans as the "superior" race.
After hearing of Ben Lockwood and his friends harassing and killing alien immigrants, Mercy met up with him and the two spoke in her car. Mercy commended Ben's work, yet remarked that he was "sloppy" as she was able to locate his fingerprints at the crime scene when he killed a Bratvik. Mercy then gave Ben a suit and proposed that they work together to accomplish their shared goal of getting rid of aliens on a much larger scale. She revealed that President Olivia Marsdin as an alien, which they wanted to expose and introduced herself and Otis. Mercy then showed Ben a file of a woman named Fiona Byrne, who was their first alien target due to her actions as an alien rights activist. The three began to work together and Ben took on the moniker, "Agent Liberty". The trio formed the Children of Liberty, made up of other humans who shared their beliefs of putting "Earth first".
Under the orders of Agent Liberty, Mercy and Otis planned to steal an EMP device from Dr. Rohan Vose. They ambushed Dr. Vose outside his lab and proceeded to use lasers to slice off the spikes on his arms in order to gain access to the lab. After Otis sliced off another spike for fun, Mercy criticized him for acting unprofessional. Just as the entrance to the lab opened, Supergirl smashed in through a window. Otis deafened the superheroine with a sonic device while Mercy cuffed her legs together. Otis then shot Supergirl out a window and the two entered the lab. Once Mercy found the package containing the EMP device, the two prepared to leave, only for Supergirl to fly back inside. Otis threw a bomb to cover their escape, forcing Supergirl to stay behind and protect Dr. Vose from the explosion. The siblings returned to Agent Liberty's lair, with Mercy informing him the mission was successful. Agent Liberty then ordered the siblings to prepare for war.
Later, at President Marsdin's gathering for aliens, Mercy and Otis were instructed to attack it and after stealing uniforms from two D.E.O. agents, they threw the EMP which turned off all the lights in which the gathering was being hosted. Once inside, Mercy murdered an agent with a gun and attempted to kill Alex Danvers but was unlucky with every shot. She then threw down her gun and the two began fighting. Mercy quickly disarmed Alex and even managed to floor her, throwing a bomb once she was down and running away. The sibling then attempted to flee on motorcycles but were followed by Supergirl. Knowing she couldn't lose her, Mercy resorted to shooting Otis in the shoulder which caused him to fly of his vehicle and was sent plummeting down, forcing Supergirl to stop and rescue him. As she did so, Mercy managed to escape. Later, back at Liberty's lair, him and Mercy watched the news report of the reveal of President Marsdin being an alien. Liberty then complimented her on her work and she explained how much she loved her country. He then moved onto a woman he had taken hostage and killed her, explaining he was an agent of liberty.
While wearing a red wig in order to not be recognized, Mercy got into an elevator with a man who was carrying a laptop with him and when the doors closed, she strangled and killed him with her bag and took his laptop. She then returned to Agent Liberty, who was watching the news report about Supergirl stopping a riot outside the White House, and exclaimed that getting the laptop from the victim was easy. She then showed him that she obtained a vial of Kryptonite and explained that they wouldn't kill her and that it was just a security measure. Mercy later used the laptop in an attempt to permanently disable any image inducer that an alien in National City was using. However, Lena Luthor managed to use her computer in her office to put up a firewall and stop Mercy. Enraged, she destroyed the laptop.
Later, Mercy travelled to L-Corp in order to destroy the image inducer for good. She used super-sonic sound waves to incapacitate everyone in the lobby of the building, including the security team, and took over the whole building. She then spoke to Lena through one of the televisions and expressed her disappointment in her for allowing her to get in so easily. One Lena got into one of the elevators with Kara Danvers and Eve Teschmacher, Mercy spoke to her again and complimented her on the way she had laid out her company.Whilst the three evaded Mercy's men, she snuck into Lena's lab and took one of the arms of the Lexosuit and came out of hiding when Lena and Kara entered the room. She asked Lena to join her because they had the same views, humans needed to focus on being as powerful as aliens. However, Lena quickly denied the offer and after attempting to talk her into it, she grabbed the other arm of the Lexosuit and shot at Mercy. She then got Kara to leave the room and her and Mercy began to fight. After failed attempts at shooting, Mercy got close to Lena and kicked her into a wall but she quickly got up and the two pointed the suit's guns at each other but before either could do anything, Supergirl showed up and pinned Mercy against a wall and managed to stop her. She was then incarcerated alongside her brother in the D.E.O.. Her and Otis' cells were later checked up on by Raymond Jensen and she attempted to convince him that the D.E.O. were the villains and that Earth didn't belong to aliens. This speech worked as Jensen later broke both Mercy and Otis out of their cells and returned to Agent Liberty's lair with them. Mercy then used a device previously used by Supergirl to defeat the Daxamites and filled it with Kryptonite, releasing Kryptonite into the air.
After they released the kryptonite, the three were greeted by Liberty, who unmasked himself in front of Jensen. Believing that Jensen had fulfilled his purpose, Mercy grabbed him and held a knife to his throat, ready to slit it, however, she was stopped by Liberty, who convinced her that Jensen could get them back into the D.E.O..
Mercy and her brother use a Hellgrammite to kill Supergirl and manipulate people as aliens are all bad. But the plan fails and Mercy is killed by Hellgrammite as revenge for his capturing and brainwashing.
- "I thought we didn't kill humans”
“He wasn't human. He was loose ends"
- —Raymond Jensen and Mercy Graves[src]
Mercy was ruthless and calculating, with a cold, stern demeanor, a stark contrast to her brother, Otis Graves' more outspoken, playful attitude. A radical xenophobic, Mercy harbors a deep-seated hatred for all extraterrestrial life, demeaning aliens as "filthy roaches" and people who disagree with her views as "Earth traitors".
- "I know that you wanna resist, but you are just like me. You don't just wanna be the best, you are the best."
- —Mercy Graves to Lena Luthor
- Peak human physical condition: As a former head of security and Cadmus agent, Mercy is in top physical condition after having undergone extensive training.
- High-level intellect/Expert tactician/Leader: Mercy is an excellent tactician, having helped Ben Lockwood gain more followers through his beliefs. As an ally of the Children of Liberty, Mercy devised several plans to spread their beliefs of prejudice against aliens, including exposing President Marsdin as an alien, forcing Supergirl to save Otis to cover her escape, and using an empath and parasite to influence aliens to attack the people.
- Computer specialist/Expert computer hacker: After stealing a laptop from an employee at L-Corp, Mercy was able to use it to hack into the company's mainframe and briefly disable any image inducer in National City that an alien was using. Mercy even designed the entire security mainframe for Luthor Corp, which she hacked into to allow Children of Liberty to break into L-Corp.
- Expert deceiver/Manipulator: Mercy has skill in convincing others to join her side. She manipulated Jensen into betraying the D.E.O. by playing on his fear after President Marsdin's unmasking and Taylor into handing over two alien convicts.
- Expert combatant/Martial artist: As the former head of security of Luthor Corp and agent of Cadmus, Mercy is a highly proficient unarmed combatant and trained in martial arts. She has proven to be skilled enough to match up against and even push back Alex Danvers, a highly skilled combatant in her own right.
- Red wig: Mercy briefly used a red wig when attempting to stay undercover and when retrieving a laptop from an L-Corp employee.
Behind the scenes
- In DC Comics and and the cartoon series Superman: The Animated Series, Mercy Graves is the right-hand woman and assistant of Lex Luthor and aided him in most of his crimes. Unlike the cartoon series where she first appeared, the comics version was also an Amazon.