Sōichirō Kamui is a young Tokyo city council member with a promising political future. He previously achieved legendary status in gaming as the sole conqueror of the notoriously difficult full-dive RPG "Kiwame Quest," earning the special title "Eternal Invincible Adventurer" under his player name, Kamui.

During his youth, he exhibited a brutal and disparaging personality, especially online. After conquering Kiwame Quest, he compiled his strategies into the "Oberdine Chronicle," sharing it online. Despite its valuable secrets, the guide became infamous for its harsh language and insulting tone, reducing its perceived helpfulness.

Professionally, he now presents a calm and soft-spoken demeanor. He possesses medium-length messy blue hair, deep blue eyes, and handsome features. While gaming, he frequently wore a charcoal-hooded black sweater, gray pants, brown shoes, and a distinctive crow mask.

Within Kiwame Quest, Kamui occasionally manifests as a ghostly vision to assist the protagonist Hiroshi Yūki during critical moments. His mastery extends to rare in-game "secret techniques" (cheats) and their effective use. The strategies from his Oberdine Chronicle remain vital for Hiroshi's progression.

Kamui's background bridges his current respected political standing and his past as a revolutionary gaming figure, reflecting a transition from ruthless gamer to composed public servant. He continues to indirectly influence new players through his documented expertise and spectral in-game appearances.