Kiara

Kiara Johnson.
She is the daughter of two super villains, Harley Quinn and the Blade Master. She was raised to be a ruthless, cold hearted killer, who did nothing but murder for money, but as she grew older, she knew that's not what she wanted. At the age of 12, she joined the Batman Family, and with the help of Batgirl, became the kid vigilante Katana.
Now, 3 years later, she is a member of Gotham High. She has forgotten about her past life, and is ready to start a new one. A better one. One where she could help people, and stop crime without killing anybody. She had friends now, best friends. She even has a crush on one of her friends, who, funnily enough, she is with almost every day. She has a crush on Jason Todd. Robin. The sidekick of Batman.
At the moment, the only thing stopping her from getting her life on is her father. He has started war with the Batman family, and had decided to team up with Ras As Ghul and the Joker. However, in the end of all of this drama, things don't end up quite as expected.