Satetsu operates as a vampire hunter within Shin-Yokohama’s Vampire Hunters' Guild, marked by a striking appearance: long silver hair secured in a low ponytail, a scar trailing from his right eye to his cheek flanked by two silver dots, and a customizable metallic left arm. His attire blends practicality with subtle flair—a dark blue long-sleeved shirt fastened by a silver chest buckle, puffed beige pants tucked into black boots bearing a white cross patch, and a black belt.

Once a delinquent influenced by American yankee comics borrowed from his younger brother, he now carries residual shame from his reckless past, adopting a quiet, restrained demeanor to shed that identity. Yet flashes of his former defiance surface when confronting threats or injustice, often leaving him acutely self-aware afterward. His redemption began after meeting Ronaldo and Gousetsu, mentors who steered him toward vampire hunting. Though committed to staying unobtrusive, he privately wrestles with envy toward Ronaldo’s renown.

A mission against Etiquette Breacher—a vampire whose ghouls specialized in petty chaos—catalyzed change. When the vampire injured John, an armadillo familiar, Satetsu erupted into brutal retaliation, threatening to cleave Etiquette Breacher’s skull. This uncharacteristic ferocity shifted perceptions; Draluc, who once dismissed him as “arm guy,” acknowledged his resolve, while Etiquette Breacher began appearing alongside him afterward, hinting at an uneasy alliance.

Satetsu’s struggle between anonymity and visibility persists. A magazine photo exposing his elephant-print boxers during a mission underscored this conflict, juxtaposing his desire for recognition with discomfort under scrutiny. Further quirks include a sexually submissive inclination, involuntarily exposed by another’s ability, and recurring anonymity—allies like Draluc frequently forget his name despite his guild standing.