- "So, I swear this began with me offering water and Band-Aids, and the next thing you know, I'm the Meredith Grey of Sherwood Forest. I'm sorry if stealing from my med school makes me a bad person."
- "It doesn't. It actually makes you deeper than I thought."
- —Mary Hamilton and Kate Kane[src]
Mary Hamilton was a medical student at Gotham University and influencer-in-the-making who secretly runs an illegal clinic to help Gotham's impoverished communities. She is the daughter of the late Catherine Hamilton-Kane, the step-daughter of Jacob Kane, and the step-sister of Kate Kane.
Sometime prior to 2008, Catherine Hamilton married Jacob Kane, and Mary met her step-sister, Kate Kane. However, being quite different from one another, the two never really managed to become close, despite Mary efforts at being friendly.
Growing up, Mary became very active on social media, to the point to be considered sort of an influencer, much to her mother's dismay. She enrolled in Gotham University as a medical student. Mary claimed it was only so she could find her "future husband", who she wanted to be a rich doctor. In actuality though, Mary was very interested in medicine and secretly became an excellent student.
At some point before 2018, Mary started to distribute water and Band-Aids to residents of the poor neighborhood of Bennett Ave. Sympathetic for the people's plight, Mary secretly began using Gotham University's funds to open an illegal clinic in the area.
The kidnapping of Sophie Moore
In 2018, she attended the switching of the Bat-Signal with her mother, Catherine. After Sophie Moore was kidnapped at the event, Mary called her step-sister Kate to come home. Mary organized a surprise welcome-home party for Kate, during which Mary talked her head off. Kate asked why she called her, and Mary revealed that she accidentally discovered a box of pictures of her relationship with Sophie, and thought that she would want to be in Gotham for her. Mary was pulled away by her mother to take a photo with a councilwoman.
The following day, Mary was working at her clinic when Kate was left on the doorstep. She was brought in and Mary helped stitch up a wound on her arm, when she explained all about the clinic, while also tending to an old man. Later a member of the Wonderland gang was brought into her clinic, and has somehow confessed Sophie's location.
Nearly killed by Alice
The following day, during breakfast, as her mother spoke about business at the phone, Mary watched a video of a baby turtle eating strawberry and showed it to an annoyed Kate. Then, after Jacob asked Kate if she wanted to reconsider the idea of joining the Crows and she dismissed it again, Mary asked if it was due to Sophie, saying she was shocked that she was now married to a man and asking out loud what was her actual sexual orientation, being cut out by Kate, who reveal to Jacob her suspicious that Alice was actually Beth, shocking everyone.
Later that day, Kate visited Mary's clinic in order to speak with one of Alice's goons she knew was brought there the previous night, and gave him a coded message to deliver to his boss. Then, after the goon was gone, Mary asked Kate if she wanted to have dinner with her, since they hadn't been able to spend time together after she came back. Kate accepted her invitation and they agreed to meet that evening out of the clinic.
Mary waited a long time but, at the time of the appointment Kate did not show up (being at a secret meeting at Burnside Park with Alice) however, after a brief blackout in the building, Chuck Dodgson appeared and attacked her with the intent of murder her on Alice's orders as she was jealous of her role as Kate's "new sister". Mary managed to defend herself by injuring Dodgson in the leg with a scalpel and locking herself in a closet, then was saved by Batwoman.
The following morning Kate visited Mary's clinic in order to apologize, however as she entered, Mary, still traumatized for the previous night pointed a gun to her then, after calming down, she scolded her for having ditched her, explaining the reason why Alice had her attacked, claiming to find it ironic, as she felt Kate didn't consider her a sister at all. Kate replied that it wasn't true but Mary didn't want to listen to her and instead asked her if it was worth it and to let Alice know that "she wasn't a threat", before to walk away in anger.
After the incident, Mary spent several night working late at her clinic and, one morning, after having vaccinated a kid and rewarding her with a sweet for not having cried after the sting, she came back to the Kane penthouse pretending she spent the whole night partying, however she was confronted by Sophie, who informed that she asked her father to be assigned to her protection due to the girl having became Alice's target.
Much to Mary's dismay and embarrassment, Sophie started to follow her the whole day, even during her classes at Gotham University, prompting her to stated that she couldn't find her "future husband" if she kept follow her around, then asking of her own marriage; Sophie avoided answering by asking instead about Kate and why she continued to refuse to join the Crows, to which Mary replied that it was because Sophie is one of them.
That night at Tommy Elliot's party, finding Mary and Sophie together in the elevator she was entered, Kate asked what was happening to which her step-sister complained about having a "baby-sitter", she and Kate mutually commented between one another how annoying Sophie was, then the elevator began a long climb dominated by an embarrassed silence.Later at the party, Mary complained to her mother about giving her a bodyguard, but she replied it was inevitable as they lived in difficult times; few moments later, having received a phone call from Alice (who was at their house) Jacob panicked and ordered his men to escort his family away, however due to Tommy having planted bombs on three elevators, Mary found herself stuck in one of it alongside Sophie and her husband, watching them bickering about Sophie not having told him she knew Kate when they were at Point Rock Academy, before they managed to escape and get her out of it.
On their way out of Elliot Tower, Mary and Sophie run in some people wounded by the explosion of the firs elevator and she managed at first sight to locate a woman who wasn't adequately rescued, making a correct diagnosis of her condition and saving her life under the astonished gaze of a paramedic and the same Sophie.
After Dodgson developed an infection due to his days of captivity at the hand of Batwoman, she brought him at Mary's clinic asking her to deal with his wound with the maximum discretion. Mary, declaring to be a "big fan" of the vigilante reluctantly accepted despite the man having attempted to kill her.That evening, while he was handcuffed to the bed and drugged with morphine, Dodgson began hallucinating, calling for his boss and lover Alice. Hearing that, Mary decided to impersonate Alice in an attempt to extorting him part of the latter's villainous plan and prompting him to reveal her that a key component to it was a mysterious figure named "Mouse". Later, Batwoman came back to the clinic asking Mary for Dodgson conditions and she claimed he was stable, also referring her what she had discovered regarding Alice's intentions, which prompted Batwoman to plant a subdermal transimitter on Dodgson in order to track him after he returned to Alice, while complimenting Mary for her work.
The next day, during a walk by the river with her mother, Catherine revealed to Mary that years ago she made Jacob believe that Beth was dead by making pass deer bone fragments for Beth's and paying the coroner to manipulate the DNA test, so that he and Kate would move on. Mary was deeply unsettled by her mother's statement, deeming it as an "horrible thing", and walked away from her in a state of shock.
Distressed, Mary got completely drunk and stormed into the Wayne Tower demanding to speak with her step-sister, being then taken under the custody of the building concierge and escorted to the head of security, Luke Fox who introduced to her as Kate's assistant explaining she was not there and that he can deliver a message to her if needed, to which Mary began a confusing explanation of which Luke understood only that her mother may or may not have killed a deer, prompting the girl to explain everything from the beginning.
Mary spent the whole day at Wayne Tower complaining about being the daughter of the "Wicked Witch of Gotham", then she realized that Alice was actually Beth as Kate had always believed and asked Luke if Kate was with her, after the latter confirmed it, Mary lashed out that Kate still favored a serial killer to her despite all her best effort to be a good sister.
After a while, still drunken due to the alcoholic beverages kept in Bruce's office, she watched the researches Luke was doing about Arkham Asylum outbreak, discovering the authorities have covered up everything about it, then she noticed the footage about Alice being the Skin Pirate and get hungry of pizza. That evening, after ordering and eating a pizza box, Mary apologized to Luke for disturbing him all day and left the building, asking him to simply tell Kate that she was sorry.
Few nights later, after Sophie was wounded in a gunfire at 200 of Rucka Avenue, Batwoman brought her to Mary's clinic asking her to take care of her and prevent her from leaving the facility. Despite her skepticism she obeyed and nursed the woman back to health; after Sophie woke up she asked were she was, to which Mary revealed the truth about her illegal clinic then, noticing she was handcuffed, Sophie asked to be released and Mary replied it was due to Batwoman's order. Frustrated, Sophie stated that the reason why Batwoman didn't want her to leave was that she knew her real identity, however Mary replied that she had no interest in that knowledge.
Later, Sophie managed to free herself and was about to leave the clinic being intercepted by Mary, who gave her some medical advises and a box of ibuprofen, urging her not to reveal to her step-father about her clinic nor Batwoman's identity due to betray people was kinda becoming "her thing" and she shouldn't hurt Batwoman the way she hurt Kate several years ago.
Then, after Batwoman came to visit her, asking about Sophie, Mary explained she had let her go despite the fact she probably knew her identity and would reveal it to the Crows' commander. Despite she expected the vigilante to be angered, she was surprised when Batwoman thanked her for saving Sophie and quietly left.
After Jacob asked to divorce from Catherine, Mary reluctantly accompanied her mother to see the lawyers; while they were on limousine she stated that she had yet to forgive her and wished to be everywhere but there with her, Catherine said that she would have understood her action after becoming a mother as well, then she was called by Hamilton Dynamics and informed of their secret weapon's disappearance as well as Dean Deveraux's death.
Later that night, Mary introduced into the Wayne Tower once again thanks to the help of her friend Carl the receptionist, to whom she offered a Frappuccino. After reaching Bruce's former office in order to speak to Kate, she waved at Luke and introduced herself to Julia Pennyworth which Kate explained was her other assistant, after Mary commented on having two assistants in a real estate firm with no real estate, Kate told her that she was busy and that would have called her the following day, prompting Mary to ask if she was at least a little shaken about their family collapsing a moment before getting out of the building.
The next day, Kate invited Mary at the first place she had bought with her firm, explaining her intention to open a gay bar in it as retaliation to Alessandro's homophobia, to which Mary gladly suggested to be the one to deal with design.
After convincing her step-father, actually Mouse in disguise, Mary went to Kate asking her to join her and her mother at Gotham's annual Humanitarian Ball where Catherine would receive the Humanitarian Award; however her step-sister stated that she couldn't forgive Catherine for what she had done, prompting Mary to said she spent the past months forgiving Beth despite being a murderer to which Kate responded it was different as she was "her family", thus deeply hurting Mary since this implied she was not. The girl then leave their bar, revealing to Kate that Jacob had accepted to do it for her.
That night, she went to the Orpheum Theatre with "Jacob" and Catherine, making a toast of champagne in the latter honor while on their limousine. Then after in the middle of her speech Catherine started to reveal a series of crimes in front of the audience due to Alice blackmail (whose men had surrounded de building infiltrating the Crows) and subsequently collapsed, Mary help to transport her to the back of the stage and called the hospital while "Jacob" left stating that he was going to look for help.
However as the man leave Alice entered the room revealing that Catherine was poisoned with an Hamilton Dynamics toxine by Mouse posing as Jacob and that she got the antidote with her. After pouring the antidote into a teacup, Alice forced Catherine to apologize to her for the years of suffering she endured because of her deception then, having received said apology, she revealed that Mary was poisoned too and that there was only enough antidote for one of them.
Obeying her mother's last wish, Mary took the antidote. She broke down in tears as Catherine declared that raising her daughter was the only good thing that she had done in her life; Catherine revealed she was aware about Mary's activities with her clinic, much to the latter's shock, and was proud of her. Catherine then succumbed to the poison and died in Mary's arms. Mary desperately tried to revive her mother, to no avail.
An upset Mary returned to her clinic, where she was reached by Kate. However, Mary spitefully rejected her step-sister, stating that if she hadn't given Beth the benefit of doubt so many times, her mother would still be alive. Mary asked one more time if "Alice was worth it", prompting Kate to finally admit she was not.
Mary is very excitable, talkative, friendly, and kind of a social butterfly; she is described as her step-sister Kate Kane's polar opposite and one of Kate trainers dubbed her as "Girl Who Talks Too Much". Despite coming off as a ditzy socialite, Mary is a very kind-hearted individual who will go to any length to help those she loves and the people in need, such as Gotham's underserved communities. Due to the bond she shares with her step-sister Kate, Mary is one of the few individuals who can talk her around.
Because of their differences however, Mary and Kate were never really close, much to Mary's dismay, though she still tried to be friendly and supportive of her step-sister. As a result though, Mary harbored some resentment towards Kate for dismissing and only seeing her as a replacement for the latter's biological sister, Beth. Mary even lashed out at Luke Fox over how Kate still favored a serial killer to her despite all her best efforts to be a good sister and began questioning Kate's love for their their family after she refused to talk to Mary since she had "work to do" when their parents were about to divorce.
Mary is also quite empathetic and sensitive; she was horrified after discovering that her mother had manipulated the DNA test on Beth's alleged skull fragments in order to gave Jacob and Kate closure, having a very hard time forgiving Catherine for this deception. Mary felt great sorrow when her mother and adoptive father were about to divorce, and was devastated for being unable to reach and act more sisterly with Kate.
Mary has often proven to be quite an assertive, inquisitive, and free-spirited girl, not bothering about being politically correct when questioning Sophie Moore's sexuality or discussing her past relationship with Kate and the impact it had on her.
- High-level intellect/Great business acumen/Skilled tactician/Leader: Mary has proven to be a very savvy, intelligent, and cunning individual. She is extremely skilled in strategizing and planning, having secretly run her own clinic without getting caught through siphoning funds from Gotham University. She dealt with various patients on her own, not having any other staff members. Mary was also very accurate at orchestrating her movements in order to cover her activities and real interest for medicine by posing as an irresponsible party girl, even to her thousands of social media followers. Mary is also a quite skilled business planner, helping Kate Kane to open her gay bar and taking over its design.
- Skilled investigator: Mary is very inquisitive and a quite capable investigator; she was able to extort information of Alice's evil plan from Dodgson while he was drugged.
- Medical knowledge: Despite being just a medical student and not yet achieving her M.D., Mary has a tremendous amount of medical knowledge, enough to operate her own illegal clinic. Her medical skills seems to be even greater and more accurate than that of many paramedics and she was able to perform various amazing feats, such as extracting a car hood out of a man's abdomen and help him recover within a night. Mary also displayed a great knowledge of injuries caused by various types of bullets, able to deduce in less than an hour how to better treat the wounds they made without using specific equipment.
- Skilled markswoman: Drawing from her knowledge on the human anatomy, Mary has an incredible aim as despite her fear, she was able to stab Dodgson in the leg with remarkable accuracy, debilitating his ability to move. Mary also knows how to use a gun.
- Network: As a member of the social elite and influencer-in-the-making, Mary has a wide array of contacts. She also has various contact between the poor Gothamite communities she helped.
- Mary loves to watch puppy videos on YouTube.
- She's a huge fan of Glam Jams.
- Mary has over 3.5 million social media followers.
- Even though Mary and Alice aren't recognized by law as step-sisters, the two have referred to each other as such.
Behind the scenes
- In the DC Comics, Mary Elizabeth "Bette" Kane is the original Bat-Girl and served as Batwoman's sidekick and Robin's counterpart. Growing up, she would adopt the alias Flamebird (and later Hawkfire) in response to her counterpart's development as Nightwing. Also in the comics, Mary is Kate Kane's younger cousin instead of her step-sister.