Thirteen years later Saki was challenged by the Ninja Turtles, who were the result of an accident exposing four ordinary turtles to radioactive waste. They were trained by Yoshi's pet rat Splinter, who had also been mutated by the same substance, to avenge his former master. After a lengthy rooftop battle where Saki seemed to be winning, Leonardo managed to plunge his sword through Saki's torso. Defeated, he was offered the opportunity to commit seppuku (ritual suicide), but Shredder refused and detonated a thermite grenade, in an attempt to take their lives alongside his own. But at the last second, Donatello used his bo to knock Shredder off the building to his death.