Rui, a Qin palace girl originally from Tonryuu, entered an arranged marriage with King Ei Sei's younger half-brother, Sei Kyou, at a young age. Initially, their relationship was strained by his unpleasant demeanor and her insolence, but genuine affection blossomed. She became fiercely protective, even hurling stones at Ei Sei when she perceived him as her husband's enemy. She possesses long strawberry blonde hair styled with two face-framing braids, full lips, and large crystal blue eyes. Her status as Princess of the Northeast is reflected in luxurious silk robes adorned with fur collars, jewels across her forehead, and a gold and diamond crown. During the Sei Kyou's Rebellion, Rui and Sei Kyou's retainers opposed his alliance with Ketsu Shi. Pleading with her husband to abandon his ambitions for the throne led to her imprisonment by Sei Kyou himself. In the Conspiracy in the Court arc, she blushed upon expecting Sei Kyou's arrival, only to encounter Ei Sei and Shou Bun Kun. She defended Sei Kyou's loyalty to Qin, arguing that any internal conflict must be secondary to confronting Chancellor Ryo Fui. Traveling to Tonryuu for her grandmother's eightieth birthday with a gift from Sei Kyou, Rui faced a Zhao attack. She accepted Ho Kaku's guidance to safety, unaware he imprisoned her under Ryo Fui's orders. Sei Kyou rescued her, but they were pursued. He held off their enemies while she fled through hidden corridors. Emerging near Shin and the Hi Shin Unit, she desperately begged them to save Sei Kyou. They arrived too late; Rui embraced her husband as he died in her arms, listening to his final words. Following his death, Rui succeeded Sei Kyou as leader of his faction. She displayed heightened determination to ensure his death was not in vain and to defeat Ryo Fui, whom she held responsible. This marked her evolution from devoted wife to active political player. Rui attended Ei Sei's coronation in You. During the ceremony, she wept, wishing Sei Kyou could have witnessed it, and was startled after seemingly hearing his voice. She later participated in the debate between Ei Sei and Ryo Fui alongside Ri Shi, Sai Taku, and the Queen Mother. Rui possesses notable political acumen, reflected in her leadership and intelligence. She holds the highest beauty stat among Qin's palace girls. A unique trait is her implied ability to sense and physically see spirits, evident during the coronation. Her residence shifted from the royal palace to Tonryuu after Sei Kyou's death, though she remained involved in Qin's court politics. A widow in her mid-twenties, her familial ties include her stepmother-in-law the Queen Mother, brother-in-law Ei Sei, and half-sister-in-law Kou.