Kioshi was elite police officer of Japan. While trying to fight off a terrorist attack from hydra he encountered Silver Samurai, during the fight Kioshi was struck down and passed away. While in the afterlife he was consumed with hatred and a desire for revenge against the Silver Samurai which caused him to be approached by Mikaboshi, the Japanese god of evil. Mikaboshi offered to restore Kioshi to life to obtain his vengeance by killing the Silver Samurai, KIoshi agreed. When he awoke he was disgusted to find that although alive he was trapped inside a darker suit of armor belonging to the very samurai he hated. He also had with him a demon possessed katana, which allows him to cut through almost anything (except adamantium and vibranium) but caused him to go into a homicidal bloodthirsty rage. He then took the name Ebon Samurai and left on his journey for vengence.
Ebon Samurai later abandoned his search for vengeance after the Silver Samurai became the head of the Japanese prime minister's security detail, and journeyed into the Microverse with Sunpyre.