The Teenage Mutant Ninja Turtles (or TMNT for short) are a team of four teenage turtles and their allies, who were trained by their sensei in the art of ninjitsu and named after four Renaissance artists. From their home in the storm sewers of New York City, they battle petty criminals, evil overlords, the Foot Clan, and Kraang alien invaders, all while remaining isolated from society (for the most part) to make sure that they don't become experimental fugitives. Ninja turtles had many incarnations throughout the years, starting with the 1984 incarnation.
The TMNT were once ordinary red-eared slider turtles born in 1997 in a pet store in New York City; when they were infants, they were adopted from the store by Hamato Yoshi, an exiled Ninjitsu master and last leader of the wiped-out Hamato Clan. When their soon-to-be father walked past a strange man, a Kraangdroid, he found something odd about him and followed. Unfortunately, Yoshi gave away his position when he stepped on a brown rat's tail. The Kraang found him and attempted to kill him, but Yoshi fought back hard. In the end, the Kraang dropped the canister of Mutagen Ooze they were holding, mutating Yoshi into a humanoid brown rat by the name of "Splinter" (after having to have stepped on that brown rat) and the turtles into a humanoid red-eared sliders (after having to have came in contact with Splinter when he was human). Splinter knew they would never be excepted in society, so he took them to the sewers, made a home down there, and made the four turtles his children. Knowing the world will be dangerous and there will be a time where they want to explore the outside world, Splinter trained the boys in the art of Ninjitsu and gave them all names from a renaissance art book that he fished out of a storm drain. Fifteen years later, a teenage girl named April O'Neil, whose Kraang-like powers is needed for the Kraang's invasion of Earth, joined them, and later her psychotic classmate Casey Jones. Soon after, Splinter's long-lost daughter Hamato Miwa joined in after being raised as an enemy of her adoptive brothers employed by Splinter's long-time enemy, the Shredder, renamed Karai.
- Leonardo is the Fearless Leader.
- Michelangelo is the Wild One.
- Donatello is the Brains.
- Raphael is the Muscle.
- Master Splinter is the Honorable Sensei.
- April is the Rookie.
- Casey is the Rebel.
- Ice Cream Kitty is the Pet.
- Karai is the Sisterly Snake.
- Slash is the Turtle Ninja Warrior.
- Leatherhead is the Heavy Duty.
- Pete is the Eyes in the Sky.
- Dr. Tyler Rockwell is the Psycho.
- Metalhead is the Mech.
- Kirby O'Neil is the Psychologist.
- Mr. Murakami-san is the Chef.
- Tang Shen is the Deceased Mother.
- Dr. Cluckingsworth M.D. is The Bird Brain.
- Kurtzman is the Kraang Expert.
- Sir Malachi is the Trickster.
- Muckman is the Trash Monster.
- Joe Eyeball is the Eye.
- Mondo Gecko is the Skateboarder.
- Napoleon Bonafrog is the Frog Nerd.