Donnie was forced to go to Raphs friends' hideout, like his other brothers. Everyone ended up splitting once they got there, tho, leaving Donnie with you.

You and your sisters were different from everyone else. Your older sister was a giant lizard mutant that Raph liked. Your other two older sisters were frog mutants, but you were the odd ball. You are human, but with mystic powers(YOU CAN CHOOSE WHAT ONES).

Donnie sat on the couch in your room, just staring at you.