Satoko Hōjō originates from Hinamizawa village, bearing significant childhood trauma. Born June 24, 1971, she used multiple surnames—Hatake, Yoshizawa, Matsūra, and Hōjō—due to her mother's frequent marriages. Distrusting her stepfathers and conflating their actions, she filed a false abuse report against Mr. Hōjō, self-inflicting injuries as evidence. During the Hinamizawa Dam Project, her parents' support made them village outcasts, subjecting Satoko and her older brother Satoshi to harassment.

Around the 1980 Watanagashi Festival, severe paranoia from undiagnosed Hinamizawa Syndrome convinced Satoko her parents intended to kill her at Shirakawa Park; she pushed them off a viewing platform, causing their deaths. An alternate account in the console-exclusive arc Mio<tsukushi-hen suggests they fell accidentally due to corroded railings as she rushed to hug them. Hospitalized at Irie Clinic, she nearly underwent vivisection as a terminal research subject but was saved by Dr. Irie's experimental drug C-103.

Placed under the care of abusive aunt Tamae and uncle Teppei Hōjō after her parents' deaths, Satoko clung to Satoshi for protection. During a later Watanagashi Festival, Satoshi murdered Tamae to stop the abuse and disappeared; Teppei fled, leaving Satoko orphaned. She then moved in with her friend Rika Furude, heir of the Furude Shrine.

Personality-wise, Satoko presents as energetic and mischievous, with a distinctive laugh and prominent canine teeth. She excels at setting elaborate traps, often targeting friend Maebara Keiichi, earning her the nickname "Trapmaster." Despite her playful exterior, she exhibits sharp analytical skills under pressure. She struggles academically, is color-blind, and her speech is polite but grammatically inconsistent.

Her relationships are defined by dependency and loss. She revered Satoshi as "Nii-Nii" (big brother), later transferring the term to Keiichi as a surrogate sibling. She also called Shion Sonozaki "Nee-Nee" (big sister). Her bond with Rika is particularly significant; they lived together and supported each other through mutual trauma.

In *Higurashi no Naku Koro ni Kai* and later arcs, her development deepens. During Matsuribayashi-hen, she used her trap-making skills defensively against the Yamainu paramilitary group. Her resilience is tempered by an inability to ask for help, stemming from a vow of independence after Satoshi's disappearance. This trait resurfaces in *Gou* and *Sotsu*. After moving to St. Lucia Academy with Rika, she struggled with the rigid environment, feeling abandoned as Rika adapted. Isolated and desperate, she encountered the entity Eua, who granted her the power to loop through time fragments. Using this, she manipulated events across timelines to break Rika's spirit and trap her in Hinamizawa, becoming the primary antagonist.

Her actions in *Gou* and *Sotsu* reveal a darker persona: calculating, ruthless, and willing to commit murder-suicide repeatedly to achieve her goals. She killed a reformed Teppei, attacked Keiichi near-fatally, and confronted a version of herself rejecting this path—dubbing her "human" self a remnant of an old fragment. This conflict culminated in Kagurashi-hen, where her "witch" self dissipated, allowing her original self to reemerge.

In the *Rei* arc, set 35 years later, she married Kisaku (grandson of village elder Kimiyoshi Kiichirō) and ran the "Smile Store" souvenir shop in Hinamizawa. They had a daughter, Sakiko, whom Satoko occasionally used for promotional activities, depicting her as a pragmatic adult remaining in the village.

An alternate version appears in *Saikoroshi-hen*, a fragment with no tragedies. Here, she never killed her parents, developing a stable relationship with them and Satoshi. Her personality diverged significantly: she spoke formally and acted coldly toward Rika, perceived as spoiled and exploitative. This version lacked close ties to Mion or Rena, socializing instead with peers sharing her refined demeanor.