Ken is the fiancé of a woman named Mari, a relationship that began before the catastrophic Great Kanto Hellquake devastated the region. After the apocalypse, they were separated and Ken believed Mari to be dead.

He was saved from a pack of wild dogs by the warlord Harlem Bomber, an event that led him to join the faction and eventually become captain of the royal guard.

While serving, Ken was tasked with searching for the giant Violence Jack. During one mission, he flew a helicopter past Mari and another woman, Yumi, though the pair hid and he departed without recognizing her.

Ken later discovered Mari after she was captured and held in a facility run by a woman named Rose. He intervened, disarming Rose with a chair and defeating several guards. He intended to kill Rose but was stopped by Mari. Ken, Mari, and Yumi then attempted to escape together.

Harlem Bomber offered Ken a deal: freedom for himself and Mari in exchange for killing Violence Jack. Ken pursued Jack and threw a knife into his eye, an injury Jack pulled out and healed from almost instantly. Ken was left bewildered as to why Jack did not kill him in retaliation.

Ken returned to Harlem Bomber's base to find it under attack and on fire. He located Mari, but Yumi died around this time. In a final attempt to escape the burning fortress, Ken and Mari boarded a helicopter. As Violence Jack fought Harlem Bomber, Mari threw a rope to Jack, who used it to swing the helicopter into Harlem Bomber, resulting in Ken's death.