Age: 16
Birthday: March 26, 1970

Gumma is an inconsiderate person. He lives with his father and his new wife with their two sons, Shouma and Yuuma. He hates his father because he blames him for his mother's death.

Gumma is childhood friends with Tamotsu. He entered the race with Hiziri upon his challenge, and wants to show his family that he can achieve his dream.