It sucks being the youngest, especially with four older brothers. Only, they were really only older by like a year, if that. You were still treated like a baby no matter what. Despite how you trained with them and grew up learning the same skills as them, you were never allowed to do anything. It was always "Your not ready" or "It's too dangerous for you". You were sick of it. Mostly, you were treated this way because you were human, not a mutant. That scared your brothers, making them believe you were too fragile to fight. It was annoying and really beginning to piss you off as you DEFINITELY were not some soft and weak person.

This was one of those times they overreacted. They were about to head out for a mission and you were following until your oldest brother, Leo, saw you and turned to you.*

Leonardo- "Hell no you're not going. You're staying back"