Teenage Mutant Ninja Turtles

"We are the Teenage Mutant Ninja Turtles. We strike hard, and fade away into the night."

- Leonardo's last line in the first issue. The Teenage Mutant Ninja Turtles (often shortened as TMNT or Ninja Turtles) are a group of four anthropomorphic turtles and the titular main protagonists of the franchise of the same name. They are named after four Renaissance artists, and were trained by their anthropomorphic rat sensei in the art of ninjutsu. From their home in the storm sewers of New York City, they battle petty criminals, evil overlords, mutated creatures, and alien invaders while attempting to remain hidden from society.

Mirage Comics
In Japan 1964, the pet rat of Hamato Yoshi, would often watch his owner as he practiced Ninjitsu and would and mimics him. Yoshi was the best warrior of the Foot Clan, but his only rival was a man named Oroku Nagi with whom he competed in all things especially for the love of the lady Tang Shen. Both tried to woo her but from the beginning she loved only Yoshi. One day Yoshi walked into Shen's home to find her being beaten by Nagi who demanded that she love him, enraged by this Yoshi fought and killed Nagi.

Yoshi's shame was great, by killing a member of his own clan he had only two options ; to end his own life and hope for honor in the next or flee to another country. Yoshi chose the latter and took Shen and his pet rat along with him to immigrate to New York.

Back in Japan Nagi's younger brother Oroku Saki vowed vengeance against Yoshi for the death of his brother. He enrolled in the Foot Clan and trained over the years to which he became their deadliest warrior. The Foot decided to expand it's influence to the rest of the world and chose Saki to lead it's American branch. Using this opportunity to seek revenge, Saki set up the Foot in New York and took on the persona of " The Shredder". He tracked down Yoshi and Shen and killed both of them in cold blood.

Yoshi's pet rat was forced to scavenged the streets for food until one day he saw a road accident involving a truck carrying toxic waste. A canister came flying out out of the truck and struck a bowl of four baby turtles which was being carried by a young boy. The canister and the four turtles fell into an open manhole. The rat followed them down into the sewers and saw the four turtles covered in the ooze which was spilling out of the now broken canister.

Not knowing exactly why, he gathered them up getting ooze on himself. He awoke the next morning to the shock that they had doubled in both size and intellect. The four turtles followed the rat everywhere except above ground. They all began walking upright but the rat received a shock when one day one of the turtles actually spoke the word "Splinter" and in doing so named the rat, soon they all began to speak.

Knowing that the outside world not understand them Splinter began training them in the art of Ninjitsu which he had learned from his Master Yoshi. With an old renaissance art book that he found in a storm drain he gave them all names ; Leonardo, Michelangelo, Donatello, and Raphael.