<Li> Casey Jones--A vigilante who wears a hockey mask to protect his identity, Casey Jones has become one of the Turtles' closest allies, as well as a love interest to April . Casey first encountered the Turtles after having a fight with Raphael . He fights crime with an assortment of sporting goods he carries in a golf bag, such as baseball bats, golf clubs, and hockey sticks . </Li> <Li> The Shredder--A villainous ninjutsu master called Oroku Saki, he is the leader of the Foot Clan, an evil ninja clan . In every incarnation of the TMNT franchise, he has been the archenemy of Splinter and the Turtles . The Shredder prefers to use his armor instead of weapons in some versions . </Li> <Li> Foot Soldiers / Ninjas--The ninjas of the Foot Clan, working for the Shredder . </Li> <Li> Karai--A female high - rank member of the Foot Clan, she has appeared in several different TMNT comics, cartoons, and films, as well as in multiple video games . In some incarnations of the character, she is closely related to Shredder as his adopted daughter or biological granddaughter . In most works, she shares an ambiguous rivalry with Leonardo, which occasionally even borders on romantic interest . </Li>

Where did the teenage ninja turtles come from