Ruri, spiritual guardian of Ishigami Village and elder sister to Kohaku, carries the legacy of her father Kokuyo as custodian of the Hundred Tales—centuries-old narratives blending myth with fragmented memories of the pre-petrification era. Her childhood bond with Chrome, forged during explorations of forests and rivers, waned as priestly duties and a debilitating chronic illness consumed her adolescence. Diagnosed with life-threatening pneumonia at twelve, she defied the elders’ grim prognosis through relentless determination, aided by Kohaku’s daily haul of therapeutic hot spring water and Chrome’s impassioned pledge to discover a cure. Assuming her mother’s role at fourteen, she mastered the Hundred Tales, transforming into the village’s unwavering spiritual anchor. Bound by custom to wed the Grand Bout champion, she maintained stoic neutrality until Senku’s accidental victory—and immediate divorce—to focus on curing her illness. Her striking features—long golden hair, sea-green eyes, and fragile stature—mirror her dual Japanese-American lineage traced to astronaut Lillian Weinberg. Initially clad in a simple blue sundress, she later adopted Yuzuriha’s tailored modern garments. Senku’s antibiotic treatment not only restored her health but unleashed latent athletic prowess, channeled into village endeavors from dam construction to battery assembly. Gentle yet resolute, she balances ceremonial solemnity with spirited assertiveness in private moments. Hyper-observant of subtle shifts in others, she deciphers Kohaku’s tactical hairstyle changes or Chrome’s gradual maturation. When invaders struck, her commanding guidance ensured villagers prioritized protecting children. The Hundred Tales’ cryptic allusions proved vital when she recognized Senku’s connection to Byakuya, directing him to his adoptive father’s gravesite message. Post-recovery, she embraced scientific collaboration, crafting communication devices and marveling at inventions like cotton candy. Though her renewed rapport with Chrome simmered with unspoken affection, she warmly accepted his earnest, fumbling marriage proposal. Her evolution from ailing tradition-keeper to dynamic civilization-builder embodies the fusion of ancestral wisdom and Senku’s scientific revolution.