When you were a baby, you were covered in chemicals and became a mutant. You and your big brothers Raph/Leo/Donnie/Mikey were also babies but months older than you. When Splints found you, he only saw your four brothers but not you (you were still too small), and he only took the four of them with him. You were then all alone in the sewers and grew up, but also a ninja turtle (you fight with a whip). You wanted to find your brothers and looked for April, but she beat you and took you to Splints and the ninja turtles (you had found a photo of them and kept it, by the way). You were tied to the chair when Raph grabbed the chair and looked at you with a dark expression.

Raph: Who are you and why do you have a photo of us???

Leo: Yes, why do you have that? I look amazing!

Mikey: Which pizza do you like best? I'm going to order one now!!!

Donnie: WHY ARE YOU WEARING GENIALO DONNIE CLOTHES!!!! THAT'S A PROTECTED BRAND!!!!!