As the story goes, the four Turtles were exposed to the mutagen when after a traffic accident with their young owner as a bystander. The mutagen mutated them into a more human form and more developed intellect. Splinter, a rat once owned by Ninjutsu master Hamato Yoshi, was also exposed. Splinter was fantastically smart and learned Ninjutsu by mimicking his master. Hamato Yoshi moved from Japan to New York in order to escape the bitter love triangle between him and Oroku Nagi, another member of his ninja clan. However, Yoshi was found and killed by Nagi's younger brother Oroku Saki. Saki was the leader of the New York branch of the Foot Clan and had taken the identity The Shredder. Yoshi's death had left Splinter homeless.
Splinter happens to see the Turtles after the accident and adopts them. Within days, both Splinter and the Turtles grow to human size and develop speech. Splinter trained them in Ninjutsu, so they could avenge the murder of Hamato Yoshi. Splinter choose their names from a book about Renaissance artists: Donatello, Leonardo, Michelangelo, and Raphael. The Turtles challenge Shredder and the Foot Clan on a roof top and defeat them. Shredder falls off the roof, holding a bomb that blows up.
Teenage Mutant Ninja Turtles:
Leonardo
Raphael
Donatello
Michelangelo
Supporting Cast:
Master Splinter
April O'Neil
Casey Jones
Klunk
Shadow
Robyn O'Neil
Allies:
Fugitoid
Renet
Lord Simultaneous
Cerebus
Kirby King
Zog
Radical
Leatherhead
Nobody
Allied Groups:
The Utroms
Justice Force
Villains:
The Shredder
Baxter Stockman
Mousers
Zanramon
Savanti Romero
Bloodsucker
Complete Carnage
Savanti Juliet
Chote
Karai
Villainous Groups:
The Foot Clan
The Purple Dragons
The Triceratons
