Ruri a gentle girl with a really submissive personality, she was ill and bedridden for a long time beccasse of an illness but her sister Kohaku cared for her everyday , until the young scientist Senku came to her village and saved her life by creating a medicine curing her form this Illness.
Ruri live in the Ishigami village that is set in the Stone Age times ,her friend are the females one like are Yuzuriha and Suika and the male one like Senku, Chrome, Kinro and Ginro