Master Splinter

Master Splinter is the adoptive father of Leonardo, Raphael, Donatello, and Michelangelo. He raised them and taught them in the art of Ninjutsu. He is portrayed as a dark gray rat in the monk's robes soon after he found the TMNT and trained them in the way of ninjutsu. When they were older, Splinter named the four turtles from a battered book he fished out of the storm drain containing the names of Renaissance artists, which he named the Turtles after. He continued to train the Turtles in every way they could, for preparation for evil the TMNT did not fully understand until The Shredder Strikes Part 1 in which the TMNT learned of the Shredder's evil and hatred and how he killed Splinter's master, Yoshi. The Turtles then forward continued to fight the Shredder to stop any evil spreading across New York and the world.