Sachiro Hirugami hails from a family steeped in competitive volleyball: both parents, his older brother Fukurō (captain of the Schweiden Adlers), and his older sister Shōko (a professional player) all played. This legacy fostered early expectations of excellence, prompting him to start volleyball young and attend the prestigious Yurisei Junior High program. There, intense perfectionism took hold; he blamed himself relentlessly for any mistake, practicing obsessively to eliminate errors. While earning an Outstanding Athlete Award, the self-imposed pressure mounted unbearably. A loss triggered a breakdown where he scraped his knuckles raw on a stone fence until teammate Kōrai Hoshiumi intervened. Hirugami confessed he might not even like volleyball, and Hoshiumi affirmed quitting was valid if it caused pain. This pivotal encounter freed Hirugami from unrealistic burdens, fostering a healthier relationship with the sport. As a second-year middle blocker at Kamomedai High, Hirugami displayed a notably calm, analytical court presence. Dubbed "Hirugami the Immovable," he gained renown for exceptional read-blocking, rarely falling for decoys and swiftly adapting to opponents' tactics. His blocking relied on keen observation of court dynamics, narrowing down attackers, and decisive reactions, effectively countering complex offenses like Karasuno's synchronized plays and minus-tempo quick. He also deployed a challenging jump float serve, marked by sudden trajectory shifts that disrupted receivers, rivaling top servers. Despite his steady nickname, he actively moved during blocks and expressed mild dislike for the moniker. Off the court, Hirugami maintained a composed, observant demeanor, often acting as a stabilizer for the energetic Hoshiumi. He openly teased teammates and opponents, prioritizing logical decisions over emotional investment, crediting his improved resilience to realizing volleyball didn't define his worth. Post-high school, he pursued veterinary medicine, becoming a fifth-year student by November 2018. This career brought new responsibilities, acknowledging mistakes here could impact lives, contrasting his earlier volleyball mindset. Family ties remained strong with Fukurō leading the Adlers and Shōko playing professionally, though he found her discussions about her boyfriend irritating. Key relationships feature his close friendship with Hoshiumi, rooted in their junior high encounter where Hoshiumi halted his self-destructive spiral. Hirugami frequently managed Hoshiumi's impulsiveness in matches and interviews. Interactions during the Spring High Nationals, notably against Karasuno, showcased his strategic targeting of pressured opponents, like exploiting Asahi's nerves with difficult serves. He adapted when surprised by evolving tactics such as Hinata's footwork-based jumps, consistently affirming that detachment from excessive "feelings" or external expectations enabled his peak performance. Physically, he stands 190.4 cm with a lean muscular build during high school, sporting wavy light brown hair and hooded eyes conveying a typically placid expression (a buzz cut in junior high). Post-timeskip, his appearance is largely unchanged aside from slightly shorter hair. Favorite foods include shu mai dumplings with large fillings. His Kamomedai statistics reflect high ratings in power, stamina, game sense, technique, and speed, with jumping as his lowest yet still competitive trait.