Ruri inherits her role as priestess of Ishigami Village from her mother. She is the elder sister of Kohaku and daughter of village chief Kokuyo. Her childhood included outdoor adventures with friend Chrome before illness struck. Contracting pneumonia at age twelve led village elders to predict a short life. Chrome vowed to find a cure during this time, while Kohaku diligently carried hot spring water daily to ease her symptoms. By fourteen, Ruri had memorized the village's oral traditions, the "Hundred Tales," fully assuming the priestess role at fifteen following her mother's death. She embodies a gentle, noble presence, though an occasionally assertive side emerges outside her duties. Prioritizing her role over personal desires, she agreed to marry the Grand Bout victor as tradition demanded. Ruri possesses sharp observational skills, noticing subtle changes like Kohaku's retied hair or Chrome's growth. Despite her illness, formidable willpower sustained her through Kohaku's care and daily hot water treatments. After Senku's arrival, she bravely risked his sulfa drug antibiotic. Her symptoms temporarily worsened as the bacteria resisted before she ultimately recovered, regaining the ability to run and engage physically after years of limitation. Her knowledge of the Hundred Tales proved vital when she recognized Senku's surname, Ishigami, revealing the village's founding by his adoptive father Byakuya and fellow astronauts. She relayed Byakuya's final message to Senku at his gravesite. Ruri exhibits exceptional memory, meticulously preserving generations of oral history. Post-recovery, she revealed unexpected strength and agility, sprinting across fields with capabilities mirroring her sister. She contributed practically to the Kingdom of Science: squeezing grapes for winemaking, crafting manganese batteries for communication devices under Gen's guidance, and modeling clothing designed by Yuzuriha. Romantic developments followed an unconventional path. After Senku won the Grand Bout, he briefly married Ruri to become chief, divorcing her immediately to focus on creating her cure. Chrome repeatedly struggled to confess his feelings, his eventual proposal described as tactless and underwhelming. They eventually married. Ruri remained present during significant events, witnessing Homura's attack on the village and observing the petrification beam at Roppongi Hills. Her story concludes with active participation alongside fellow villagers in rebuilding civilization.