Satetsu hunts vampires in Shin-Yokohama under the Vampire Hunters' Guild. He possesses long silver hair tied in a low ponytail, slim eyes with small black pupils, and a jagged scar running from his right eye to his cheek, accompanied by two silver dots. His attire includes a dark blue long-sleeved top secured by a silver chest buckle, beige puffed pants tucked into black boots displaying white cross patches, and a metallic left arm covering he notes is interchangeable. Personality-wise, he appears reserved and soft-spoken, often perceived as unremarkable. This demeanor is a deliberate effort to distance himself from an aggressive delinquent past influenced by American yankee comics borrowed from his younger brother; he feels deep shame over those outbursts and strives for composure. Witnessing injustice, especially against others, can still trigger his former aggression, followed by embarrassment. During a confrontation with the vampire Etiquette Breacher (Manabu), who uses ghouls for petty crimes, Satetsu's frustration over his lack of recognition compared to hunters like Ronaldo leads him to partner with Draluc. When Etiquette Breacher kicks Draluc's armadillo familiar John, Satetsu violently threatens to split the vampire's head in half. This protective fury surprises Draluc, who subsequently uses Satetsu's real name instead of nicknames like "arm guy" or "Mr. Elephant Pants" – the latter referencing Satetsu's exposed elephant-patterned underwear during the fight. Satetsu quickly reverts to calm politeness to resolve the situation, highlighting his internal conflict. The encounter shifts his relationships: Etiquette Breacher develops respect for him, and they are often seen together afterward. A magazine publishes a photo of Satetsu in his underwear from the incident, increasing his unintended notoriety. His delinquent past is later mocked by Ronaldo, with flashbacks showing a younger, bandaged Satetsu possessing a human left arm; the reason for its prosthetic replacement remains unspecified. Trivia notes include his submissive sexual orientation, inadvertently revealed by Mr. Lewd Talk’s power, and Draluc habitually forgetting his name, reinforcing his struggle for recognition.