Ruri is a descendant of modern-day humans. She is Kohaku's elder sister and the daughter of Kokuyo, and serves as the priestess in Ishigami Village. Ruri is a young woman with a delicate face, long blonde hair, and blue-green eyes. Her hair reaches her waist, and is cut in choppy layers at her shoulders, chin, and eyebrows. Her eyebrows and lips are thin, while her eyes are large with a slight point towards the upper outer edge, giving her a calming, mature expression. She appears to have a mix of Japanese and American descent, denoting her heritage as a descendant of Lillian Weinberg. She shares similar facial features with her younger sister, Kohaku, but has longer, squarer hair that she wears down rather than up in a ponytail. Ginro crudely pointed out that Ruri has bigger breasts than Kohaku. She wears a primitively-made blue sundress that reaches her ankles, with a split along her left leg, going up to her waist. It is clasped in three places along her thigh for modesty. High on her waist, she wears a thin rope tied into the shape of the village's star-shaped symbol, and wears the village rope around her neck. She also wears the same sort of heeled shoes as the rest of the village. When Yuzuriha built a fashion store, Ruri wore a more modern dress. Ruri is a gentle, kind, and noble young woman with an aggressive personality that occasionally comes out when she's not acting as priestess nor dying of pneumonia. She has incredibly strong willpower, surviving pneumonia through sheer will and Kohaku's help. In Ruri's mind, acting as priestess for the village comes first: she was willing to marry whoever won the Grand Bout as was tradition, and diligently memorized all 100 Tales in two years before her mother died. She also tried passing the tales to Kohaku before she died, but Kohaku refused, which may have helped Ruri's determination to survive rather than accept her fate of a short life. She cares a lot about Kohaku, her younger sister, and frets over her. When she noticed that Kohaku's hair was tied differently, she expresses concern over Kohaku behaving recklessly and getting into accidents. Ruri pleads to her to take care of herself better, for her sake. When they reunite after Ruri's revival, Kohaku is the first one Ruri goes to to hug. After recovering from her illness, she is shown to be just as much of a tomboy as Kohaku, breaking into a sprint as soon as she is let loose. Her keen memory and ability to learn quickly puts her in charge of building the dam. She also helps Senku with solving the mystery of where the villagers came from by pooling her knowledge of the Hundred Tales and his knowledge of the modern world.