Shin is the successor of Nanto Koshū Ken ("South Dipper Lone Eagle Fist"), one of the martial art styles within the Nanto Rokusei Ken. He bears the destiny of the Star of Martyrdom, who is destined to live and die for love.

Shin secretly desired Kenshiro's fiance Yuria since as long as he remembers. After the nuclear war and the death of Master Ryuken, Shin was persuaded by Jagi to challenge Kenshiro and take Yuria by force. Shin defeated Ken and engraved the seven scars on his chest as a reminder of his defeat.

Afterwards, Shin assumed on the name of King and expanded his organization, building Yuria the city of Southern Cross to win her affections. However, his continued atrocities only drove Yuria to commit suicide by leaping off the top floor of Shin's palace. Yuria survived thanks to the intervention of the Nanto Gosha Sei, who arrived on Southern Cross to protect Yuria from Raoh's impending invasion. Shin entrusted Yuria to the Goshasei's custody and allowed his reputation to be tarnished by pretending that he was her murderer.

One year after their initial battle, Ken and Shin fought each other once again within Shin's palace. Motivated by the "tenacity" Shin taught him after their first battle, Ken overpowered Shin and struck his vital points in the shape of Shin's emblem - the Bloody Cross. Maintaining that Yuria had died, Shin refused to die from Ken's technique and took his own life by leaping off the balcony of his palace, as Yuria did before him.