Moutoku Sousou began as a common fighter, enduring childhood bullying until Chuukou Kyocho defended him, forging a formative bond. A pivotal moment occurred when Sousou discovered Kyocho assaulted by fellow dojo students, triggering his first dragon awakening and the attackers' deaths. This established a violent pattern tied to his dragon spirit, including killing Bunyaku Kansui—sparking Mouki Bachou’s vengeance quest. Leading Kyosho Academy, Sousou initially displayed laziness and apathy, frequently sleeping while delegating duties to subordinates like Hokou Kakuka and Genjou Kakouton. His appearance evolved: long dark brown hair, unbuttoned shirts, and bare feet shifted to crimson red hair and yellow eyes, mirroring his transformation. The dragon’s awakening after Yoshu assassin Koshaji wounded Kakouton marked Sousou’s descent. Enraged, he effortlessly killed Koshaji, intensifying the dragon’s hold. He grew violent, power-obsessed, and tyrannical—ordering Yoshu Academy’s destruction and executing perceived traitors like Bonsoku Ukin. Driven by the dragon’s hunger, he targeted formidable fighters, especially Unchou Kan’u. Capturing Kan’u to quell the dragon backfired; her presence hastened his possession. Sousou’s fleeting lucidity surfaced when he begged Kakouton to imprison him underground, fearing his violence. Kyocho intervened, calming him with her chi and reaffirming their bond. Yet upon learning Kakouton freed Kan’u, Sousou branded him a traitor and nearly killed him, severing his last human tether. Fully consumed by the dragon, he faced Gentoku Ryuubi and Hakufu Sonsaku at Red Cliffs. Initially dominant, Sousou overpowered them and devoured Gentoku’s dragon. But Hakufu’s controlled dragon and Gentoku’s mastered lightning dragon reversed the battle. Their combined force annihilated Sousou’s dragon spirit, ending his reign.