The "Teenage Mutant Ninja Turtles" are named Leonardo, Michelangelo, Raphael and Donatello. The creators of the franchise, Kevin Eastman and Peter Laird, named the characters after famous Italian Renaissance artists.
Though the "Teenage Mutant Ninja Turtles" are named Leonardo da Vinci, Michelangelo, Raphael and Donatello, they frequently use shortened nicknames for each other, which are Leo, Mikey, Raph and Donnie. Each Ninja Turtle has a distinct personality and role in the group: Leonardo is the leader, Michelangelo is the comic relief, Raphael is the "bad boy" and Donatello is the peacekeeper. In addition to the Ninja Turtles, other prominent characters include Splinter, April O'Neil and Casey Jones.