Rika Furude, heir to the Furude family and shrine maiden of Furude Shrine, belongs to one of Hinamizawa's three great households. Villagers revere her as the reincarnation of Oyashiro-sama, a status stemming from her position as the eighth consecutive firstborn daughter in her lineage. This grants her significant influence, though her young age excuses her from village meetings. Her parents died under suspicious circumstances tied to Hinamizawa Syndrome research; her father was drugged by the Yamainu, and her mother underwent vivisection after being identified as the Queen Carrier. Mayor Kimiyoshi adopted Rika afterward, but she lives independently near the shrine with her close friend and classmate, Satoko Houjou.

Rika possesses the ability to loop through timelines upon death, facilitated by Hanyuu, the true form of Oyashiro-sama. This looping spans roughly a century of repeated Junes, with Rika retaining memories of every iteration. Her primary goal is to prevent her own death, which historically triggers the Great Hinamizawa Disaster—mass insanity among villagers infected with Hinamizawa Syndrome following the Queen Carrier's demise. The psychological toll of countless loops erodes her initial optimism into resignation and cynicism. She maintains a deliberate childlike facade in public, using phrases like "nipah" and "mii," and ending sentences with "nanodesu" to appear harmless. This contrasts her true personality, revealed privately or under stress: a weary, apathetic adult voice using the pronoun "watashi," displaying blunt pragmatism and occasional hostility. She indulges in wine and spicy foods, partly to annoy Hanyuu through their shared senses.

Years after achieving a timeline where Miyo Takano's plans are thwarted, Rika and Satoko enroll at St. Lucia Academy. Rika adapts seamlessly to the elite culture, excelling socially and academically. Her immersion in new friendships and adherence to formal etiquette inadvertently neglects Satoko, who struggles. A rift deepens when Rika offers tutoring, which Satoko interprets as condescension. After Satoko murders her at St. Lucia, Rika awakens in June 1983, forced into new loops. In these cycles, she initially suspects Takano has resumed her schemes but observes deviations: Keiichi survives lethal injuries, and friends exhibit paranoia without Takano's involvement. She dies repeatedly, including bludgeoning by Kuraudo Ooishi and Keiichi Maebara.

Hanyuu temporarily aids her before vanishing, leaving Rika to navigate the loops alone. She deduces another looper is sabotaging her efforts and confirms Satoko's role by testing her with a rigged gift box—a prank Satoko anticipates due to her own looping. Rika eventually obtains the Onigari-no-ryuuou, a sword capable of permanently killing loopers, intending to use it against Satoko. In the manga adaptation "Meguri," Rika actively collaborates with allies like Jiro Tomitake to counter Takano early and displays heightened strategic aggression against Satoko, including strangulation deaths.

Physically, Rika appears petite with indigo hime-cut hair and purple eyes. At St. Lucia, she wears the academy's uniform: a long-sleeved white blouse, calf-length frilled socks, and red Mary Jane shoes. Her eyes shift to blazing red when employing her adult persona during loops. Her demeanor evolves across timelines; early loops show hopeful resistance, while prolonged failures breed detachment. Post-St. Lucia, she initially dismisses Satoko's struggles but later confronts her directly, culminating in violent clashes within the loops.