Seiichirō Takamine is the second-in-command of the Yamainu Squad, a specialized unit confronting supernatural dangers within a larger organization focused on maintaining order. At 36 years old, he stands 183 cm tall, weighs 80 kg, and has blood type B. Known for his quick temper, he also enjoys alcohol. As a seasoned warrior within the Yamainu, his duties involve operations against the Orochi and related threats, wielding an oversized sword resembling a meat cleaver in combat.