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 which is the source of his great strength and skill. This scar is also a sign that he's destined to overthrow his real father. 

Riki's mother was executed for poisoning 13 infants, and Riki and his brother Nachi escaped prison 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 Girlfriend/Childhood friend was driven to death by Yakuza (although the Yakuza only caused her to quickly commit suicide after being kidnapped). This lead Riki to murder the Yakuza which sent Riki to jail. He keeps the 5 bullets that the Yakuza shot him with in his chest as "souvenirs". 

After Riki escapes jail he searches for his brother Nachi.