Shredder

Shredder was a friend and rival of Hamato Yoshi, when he was still known as Oroku Saki. Wanting to take his place within the Foot Clan, he betrayed him and had him banished. He took control of the ninja clan and diverted it to become a criminal organization that reigned terror in Japan. He also allied with the alien banished from Dimension X, Krang, who wanted to conquer the galaxy, and therefore the Earth. He provided him with new robotic soldiers who offer an excellent distraction for the turtles.