A man born with super human strength that can resist even bullets, similar to Kenshiro of Hokuto no Ken. He also heals much faster than a normal human. He was separated from his younger brother Nachi since childhood and was adopted by the Saiga family. He has a scar in the shape of the Star of David on his right hand.

Riki's mother was executed for poisoning 13 infants, and Riki and his brother Nachi was carried away from the prison by a caretaker before they were dealt with punishment. Zhāng Shàn-Guǐ stopped Riki from committing suicide infront of his mothers grave and became Riki's sifu in the ways of Qi Gong.

Riki's friend, Keiko, was hit by a car - although the wounds weren't life-threatening, she later fell into a coma in the hospital due to low-grade painkillers, which was opium supplied by South Port gang. This lead Riki to murder the gang leader which sent Riki to jail.

He keeps the 5 bullets that the Yakuza shot him with in his chest as "souvenirs".