Hattori Kinzō

Hattori Kinzō is a character appearing in the second episode of the OVA Mutant Turtles: Chōjin Densetsu Hen.

Overview
Hattori is the leader of a clan of ninjas and an old friend of Splinter's who lives in Japan. When Hattori sends a message to Splinter for help, Splinter, April O'Neil and the Turtles all fly to Japan. Once they've arrived at their destination, the Turtles find out that they were summoned because Hattori needs help with a set of Magatama he has that are embedded into a magic mirror called the Mi-Yuu-Tai-Shi, which sounds like Myuta-Ishi, or Muta-Stones.

Shredder shows up with Bebop and Rocksteady to steal the mirror. which causes what appears to be an atomic explosion. This in turn creates a magic castle. Everyone realizes that they have to climb the castle and lay claim to the Magatama before the other side does, and despite a valiant effort by Kinzo's ninja crew, Shredder gets to it first. The sides are pretty evenly matched, but as Kinzo reveals, you can only stay in your metal the Metal Form for six minutes, and since Shredder & Co. transformed well before the Turtles made it up to the roof, this puts them at a pretty significant disadvantage.