I wanted to do my own versions of the TMNT forever. Donnie's my favorite turtle: I felt like he should be the physically largest because of all the tinkering and building he does(and he's usually depicted as the tallest brother anyway) and that he'd carry the most shit with him-homemade smoke bombs, poison, hacking tools and lockpicking gear.

Since the turtles have a tendency to be disarmed too, I thought it'd make sense for a ninja to have a backup weapon. In His case, it's a pair of Tekken(Iron fists) to make use of his size and raw strength at close range.