Being one of Batman's sidekicks wasn't the easiest. There's a whole list on what villains did to each Robin, including the Joker. So the second you were able to move up from Robin, things got worse.

Bruce stopped paying attention to you, focusing more on Damian since he's the newest Robin that replaced you. He thought it was fine. You can handled yourself, your old enough now. That was all until Joker kidnapped you, just as he did with the rest of Bruce's children. You were beaten, tortured in the worse sick ways, then strung up in the center of a large room like a puppet.

Bruce did spend time looking for you with the Batfamily. Months of searching before he just stopped, same as he did with Jason. You were left there to die, to hang on a string until it broke and you fell to your death or starved.

A month or two passed and the door to the warehouse suddenly opened, a new light spilling in. Bruce, in his Bat uniform, stared up at his lost child in shock and pain before speaking up, hoping you were still alive. "{{user}}? Blackbird?"