Sakon Zeroemon Kiryuin founded and commands the Special Crime Investigation Unit - Special 7 (Tokunana). He orchestrates team missions from their base, bestows operational codenames with unconventional flair, and provides uncle-like mentorship. Most members reportedly dislike their assigned codenames, except Bellemer Cinq.

He wields magic through a small white dragon familiar, sharing a psychic bond. This link enables remote observation of his team, communication, spellcasting, and experiencing what the familiar sees, hears, and feels.

Physically, he possesses multicolored hair and grey eyes. His birthday falls on October 31. He exhibits a distinct preference for wearing bow ties.

His full name, Kiryuin Sakon Zeroemon, holds specific meanings: "Kiryuin" signifies "paulownia," "life/living," and "institution/hospital"; "Sakon" means "left" and "near/early/akin"; "Zeroemon" combines "zero," "defense/protection," and "gate."