The Foot Clan are an insidious ninja clan founded by the UtromCh'rell, under his guise of Oroku Saki, during feudal Japan. Although Ch'rell, as Saki, maintains an outwardly altruistic appearance to the world, the Foot Clan secretly divulges in a number of criminal activities. He also regularly antagonizes his enemies without provocation - at first just the other Utroms on Earth, but after slaying the Utrom Guardian Hamato Yoshi, the becomes a target - and vice versa - of Splinter and the Ninja Turtles.
"They are known only as the Foot, and few who encounter them live to tell the tale. They are the best trained, most lethal ninjas on the face of the planet. At least...the best non-turtle ninjas. They are cunning thieves and relentless warriors. Their mastery of weaponry is unsurpassed and they're always full of surprises. Where did they come from? Who do they work for? Well...that's still a mystery to us. But we seem to have a knack for running into them. And they're just one more reason the surface is a dangerous place for a turtle."
— Leonardo from Teenage Mutant Ninja Turtles 3: Mutant Nightmare