Susanoo manifests as a divine entity locked in battle against an ancient dragon lord. To confront this dragon—which has possessed a high school girl named Terumi—Susanoo requires a human host. He selects Kouichi, securing the young man's reluctant consent due to the dire stakes.

Operating through Kouichi's body, Susanoo uses it as a vessel to engage the dragon. His singular objective remains the dragon spirit's defeat, an act that would inevitably kill Kouichi. This forces Kouichi into a dual struggle: aiding Susanoo as his vessel while desperately seeking to save Terumi.

A priestess named Sayoko reveals the broader context of a celestial war between gods, framing Susanoo's actions and motivations solely within this divine conflict. His role remains defined by this larger struggle, devoid of personal evolution or history.