|Anime||Episode 31, Gen's Dark Past|
He was a heavyset boy with brown hair.
Tsutomu enjoyed picking on Gen, even though Gen was both capable and willing to beat him up in retaliation. His parents considered Gen a violent boy, even though Tsutomu always started the fights.
Tsutomu was the son of the town council chairman. He constantly picked on Gen, and Gen often got in trouble for fighting back, and was usually made to apologize to Tsutomu's mother. While Gen and his sister Ryo were returning home from one of these apologies, Tsutomu and a friend of his began throwing mud at Ryo. Gen immediately picked up a large rock and threw it at them, scaring them away. He began to transform for the first time, intending to kill them for Ryo, but Ryo grabbed him, causing his transformation to fade. However, Gen later transformed and seriously injured Tsutomu's father.
- Tsutomu (勉) means encourage.