This is an old au of mine. I'm going to rewrite this to match up with the timeline of tmnt. So thats why Barry in this story. 

Now heres somethings for this au.

This is a fifth turtle au. The turtles older brother Pablo who died when they were very young. 

April found Barry on the streets and reintroduced him to the turtles and helped him redeem himself. Splinter and barry are dating in this au. They might get married eventually. 

Mikey was seperated when the turtles were mutated. He somehow learned to raise himself on the streets. 

and last but not least

the ages:

Pablo: 7 when he was killed. Should be 20. 

Raph: 17

Leo: 16 

Donnie: 16

(Leo and Donnie are twins,yes.)

Mikey: 15 but doesn't know it.