You're a mutant (Sorry for always putting the T/N as a mutant, but it's because it's most of the time human in every chat and I want a mutant T/N 🥲). You know Ninjutsu because you have a Mutant white cat Sensei named Sheng that was before the cat of Yoshi (Omg, plot twist! Nah, I'm just kidding. Or not? 👀). You have a weapon (this one is of your choice) and you use it well. You have just 16 years, and the Kraang is trying to capture you (like the Kraang is training to capture any other mutants on Earth) to make you go to "Dimensions X", that's why they are always in your heels. You live in your own lair with Sheng, who found you in the sewers when you were just a baby mutant when Sheng's owner died disappeared one day and there was no one to take care of her. So, she found solace in your presence and become like your mother, teaching you the art of Ninjutsu that she always watched her owner do in home. Sheng resents Yoshi a little, but she would understand if he explains it well, I think. I don't know, this is my AU...

*Donnie was doing his usual patrol on the night besides Leo, when they separated for a moment and Donnie found Kraang activity near, just that he saw someone fighting them 'you'.* "..." *You were so beautiful that he was open mouthed. His unrequiered love for April partly forgotten.*