Jonathan Cartwright

Jonathan "Johnny" Cartwright, known as Mouse, is a member of the Wonderland gang with the innate ability to impersonate anyone, as well as the accomplice and brother-figure of Beth Kane. He is also the son of August Cartwright.

Early life
Jonathan Cartwright was born in Gotham City to August Cartwright and an unknown mother. They lived in a rural area just outside the city; at some point in his life, Jonathan had an unspecified accident that leaved him hideously disfigured, causing other people, especially children, to call him a "monster", hisolating him and forcing him to stay always alone without any friend.

Meeting Beth
In January 2003, while he and his father were out fishing, they found Beth Kane, washed up on shore after the car accident that killed her mother. They took her back to their home and when she woke up Beth was immediately terrified, only wanting to see her father again. August tried to calm her down and explained that he wanted Beth to become friends with his son. She constantly screamed at him to allow her to go home, but he only left to get her a sandwich. Then the girl asked Johnny why he covered his face only to learn that he is afraid of scaring people, and she explained that he didn't scare her.

Later, while Beth and Johnny were watching television, he showed her his ability to mimic any voice he hears perfectly, then a news report of the girls disappearance came on and she asked August why he hadn't called the police, however, he never answered but instead grabbed her and threw her into the basement and locked the door, later telling her that the only reason she was there was to become friends with his son.

Later, Beth managed to get to open the door, making her way to the kitchen and calling her father to ask for help, only to be cut off by August who grabbed the phone, ripping it off the cord, warning her that if anyone came for her, he would kill them and threwing her back into her cell right before instructing Johnny on mimic Beth's voice after Jacob and Kate Kane showed up at the house, demanding to know where Beth was. Though reluctantly, the boy executed his father's order and August managed to make Jacob believe that it was Johnny pulling a prank after having heard Beth voice in an video shown in television, prompting Jacob and Kate to eventually left.

Johnny then approached the door of Beth's cell, while she was crying, telling her he wanted to be her friend and sliding the book, Alice in Wonderland, underneath her door in order to keep her company.

Over the following years, Beth and Johnny build a sibling-like relationship, to the point that the boy is said to be the most important person to Beth.

Sent to Arkham
At some point, Jonathan started to use the nickname "Mouse" and was sent to Arkham Asylum for unknown reasons, but he managed to escape during the outbreak caused by John Deegan.

Working with Beth
Two weeks after his escape, while Beth was held captive by her sister Kate and convinced to tell her what happened to her after she survived the accident, Mouse approached the two while they were stopping at Dusty's Roadside Diner during a trip on the road to the place that marked Beth's destiny and, posing as a waiter, he managed to drug Kate and take her to the Cartwright's old house.

After Jacob Kane and Sophie Moore found out that Kate was helded at the shacks, they were confronted by Beth and Jonathan. While Beth took care of her father managing to stab him, Mouse attacked Sophie mimicking Kate's voice and nearly managing to subdue her before she knocked him loose and he stops to put the skin graft on his face back on. As Kate arrived, she holded a gun to Mouse's head, and entered the house right before Alice could kill Jacob, telling her to decide which is more important to her: killing Jacob or keeping Mouse alive. Alice figured that Kate was bluffing, but Sophie came in aiming her gun at her. Irritated, Alice said that killing Jacob would be too easy and if they all walk out, no one had to die. Kate released Mouse and he leave with Alice.

Later, Mouse and Alice were reunited once more, and he surprised her with a copy of the same book he gave her many years prior, assuring her that he would escape her pool of tears. Alice said that he saved her, and gave him the face that she assembled from her stint as the Skin Pirate. Mouse said that he loved her, and Alice told her "dear brother" that she loved him too and she can help him became anyone he wanted to be. She vowed that once they're done with Jacob, he would never forget about her again.

Abilities

 * Voice mimicry: Mouse has the innate ability to mimic the voices of others exactly. He has used this talent to mimic various characters, such as Beth and Kate Kane.
 * Expert hand-to-hand combatant: Jonathan is proven to be a fearsome hand-to-hand combatant, as he was able to match and nearly best a highly skilled Crows agent such as Sophie Moore in hand-to-hand combat.
 * Stealth: Jonathan has great skills in stealth. He was able to sneak up on Sophie Moore without her noticing him.

Behind the scenes

 * Johnny is the first case of gender-bending in since he's based on the villain Jane Cartwright aka Jane Doe, who first appeared in the Gotham episode "Nothing's Shocking". She was a serial killer and an Arkham Asylum patient, who was under the psychological delusion that her face was hideously disfigured and wore a mask at all times. She had the ability to shapeshift into other people by touching their skin.
 * She was based on a comic book Batman Villain named Jane Doe, who is a master of disguise and she has the power of mimicry.
 * Johnny is also the second case of gender-bending in the Arrowverse where a female character was changed into a man. The first is Lucious Coolidge.