Satoshi Houjou stands as a pivotal character, chiefly known as Satoko Houjou's older brother. Born June 16, 1968, he shares Satoko's struggle to differentiate cauliflower from broccoli, hinting at potential color blindness. After their mother's successive remarriages, the siblings bore surnames Hatake, Yoshizawa, and Matsūra before adopting Houjou from their fourth stepfather. Both parents perished in an accident during the Watanagashi Festival, marking the second victims in the Series of Mysterious Deaths; their stepfather's body was found, but their mother's remains vanished. Following their parents' deaths, Satoshi and Satoko endured guardianship under aunt Hōjō Tamae and uncle Hōjō Teppei, suffering severe physical and emotional abuse. Satoshi routinely shielded Satoko from violence, accelerating his physical and mental decline. Combined stressors—abuse, village ostracization over their parents' dam project support, and Satoko's deteriorating psyche—ignited Satoshi's Hinamizawa Syndrome, manifesting paranoia, auditory hallucinations of footsteps, and depression. During the 1982 Watanagashi Festival, Satoshi killed Tamae with a baseball bat to halt her abuse of Satoko. Days later, en route from Okinomiya after buying Satoko a giant birthday teddy bear, he hallucinated bystanders as his dead aunt. Dr. Irie Kyōsuke intervened, confining Satoshi to the clinic's underground facility under sedation for terminal-stage Hinamizawa Syndrome. Authorities masked his disappearance with claims of a transfer or "demoning away," fabricating sightings of him boarding a Tokyo-bound train. Satoshi lingered comatose for years, inadvertently aiding Irie's development of a Syndrome treatment. In *Matsuribayashi-hen*, Sonozaki Shion—who deeply cherished him—uncovered his condition during a clinic infiltration. Alternate timelines diverge: *Saikoroshi-hen* depicts him thriving with his parents in a tragedy-free world, while *Rei*'s 20th-anniversary manga shows him marrying Shion and residing in Hinamizawa decades later. The *Sotsu* anime concludes with his 1987 awakening, and the *Gou* manga adaptation features Satoko briefly visiting his comatose form. His relationships anchor narrative arcs. His protective yet strained bond with Satoko precipitated his psychological collapse. Shion's fixation on his disappearance drove her vengeance in *Watanagashi-hen* and *Meakashi-hen*. He shared brief connections with Ryūgū Rena over mutual trauma and Sonozaki Mion, who ceded romantic feelings for him to Shion. Keiichi Maebara initially resented him for "abandoning" Satoko but later revered his baseball bat as a spiritual safeguard. Physically, Satoshi possessed blond hair and red-violet eyes, standing marginally taller than Keiichi. He commonly wore his school uniform, baseball attire, or a clinic gown. His personality merged quiet reserve with fierce protectiveness; friends like Mion and Irie observed his airheadedness and exhaustion-fueled clumsiness, though kindness endured until his mental fracture. He frequently used the verbal tic "Muu" (むっ) when distressed.