Kaioh ruled as First General of Asura, commanding the Land of Shura with absolute power under the titles "Creator of the New Century" and "Demon Kaioh." Eldest brother to Raoh, Toki, and Sayaka, he was born to servants of the Hokuto Sōke Clan in Taiseiden. A fire at the ancestral home saw his mother sacrifice herself to rescue two Hokuto Sōke infants—later known as Hyoh and Kenshiro—while she carried the unconscious Toki to safety. Her dying words, stressing eternal servitude to Hokuto Sōke, deeply scarred Kaioh. He and Raoh buried her secretly at Lake Masho. Kaioh then renounced love and embraced evil, symbolically killing his pet dog to sever his humanity. As a youth, Kaioh mastered Hokuto Ryū Ken under Jūkei, yet endured forced defeats in sparring matches against Hyoh to bolster the younger boy's confidence. This humiliation, combined with Jūkei's threats against his siblings, ignited his hatred for the Hokuto Sōke lineage. Kaioh later brainwashed Hyoh using pressure points, erasing his memories of Kenshiro and implanting the belief they were brothers. Together they conquered the Land of Shura, establishing a tyrannical rule alongside Han as one of the three Rashō. During the Land of Asura arc, Kaioh kidnapped Lin to lure Kenshiro into his territory. He overpowered Kenshiro, exploiting Musou Tensei's vulnerabilities, and crucified him for execution. After Kenshiro escaped with allies like Shachi and the pirate Akashachi, Kaioh murdered his sister Sayaka to frame Kenshiro, aiming to provoke Hyoh into a vengeful rage. He further tormented Lin by revealing his resemblance to Raoh and striking her with a pressure point designed to erase her capacity for love, ensuring she would fall for the first person she saw upon waking. Kaioh pursued Shachi to the Hokuto Sōke's sacred temple to block Kenshiro from learning Hokuto Shinken's foundational secrets. There, Shachi temporarily overpowered him, empowered by a goddess statue embodying the love Kaioh despised. Their final battle occurred at Lake Masho, where Kenshiro used the sealed testament of Hokuto's founder to counter Kaioh's techniques, including the Anryu Tenha levitation field and Seimyo Danretsu energy blasts. Defeated, Kaioh expressed regret when the dying Hyoh forgave him instead of seeking vengeance. Kaioh carried Hyoh's body into a lava flow, creating a statue of them both before submersion. Kaioh mastered Hokuto Ryū Ken to its pinnacle, generating a potent, visible Matōki aura requiring armor for containment. This aura manifested as a demonic phantom ("Genma Eirei") and unleashed energy projectiles or geyser-like eruptions. His signature techniques included Anryu Tenha to disorient foes and pressure-point strikes inducing cellular decay or emotional manipulation. He also possessed knowledge of Hokuto Sōke no Ken, the precursor style to both Hokuto Shinken and Hokuto Ryū Ken.