Sumi was a secondary villain appearing in the Jonny Quest episode The Dragons of Ashida.
He was the hulking servant of Dr. Ashida, Sumi is the one who trained Ashida in the art of Judo and Karate, a wrestling champion who retired without ever losing a match. Sumi looked after Ashida's "dragons," and was the only human that the giant lizards feared. He was missing his left eye and wore a patch to cover it.
Despite his loyalty and usefulness to his employer, the cruel Ashida treated Sumi harshly, subjecting him to multiple beatings whenever he displeased him and constantly threatening to feed him to the dragons. Eventually, Sumi grew tired of Ashida's brutal treatment of him. He threw Ashida into the pit with the dragons, where the reptiles devoured the evil scientist. Afterwards, it is assumed that Sumi remained living on Ashida's island.