Born into the Hyou clan, Hyou Shusui was initially deemed powerless. This led to her brainwashing and transformation into one of the clan's Assassin Dolls. Her exceptional beauty later secured her selection as the next attendant and potential vessel for the Red Immortal, or Rose Princess. Kou Shouka intervened, rescuing both the Red Immortal and Shusui. He adopted Shusui and sent her to the imperial palace to serve as a lady-in-waiting, granting her a chance at an ordinary life. Physically, Shusui possesses pale skin, waist-length wavy olive-brown hair, and deep blue eyes. Her appearance was renowned throughout the Imperial Harem, with Emperor Shi Ryuuki noting her beauty rivaled only Kochou, a famed courtesan from the Red Light District. Personality-wise, Shusui maintains a refined, graceful demeanor, often seen as the perfect lady. She exhibits strictness, particularly toward Ran Shuuei, frequently admonishing his behavior. Beneath this lies a kind, gentle nature, concealed from most due to fears rooted in her Hyou clan brainwashing. She reserves this softer side for Kou Shouka, Kou Shuurei, and Shi Ryuuki. Her narrative arc begins as Chief Lady-in-Waiting for Kou Shuurei during Shuurei's tenure as Emperor Ryuuki's consort. Concurrently, she serves as an assassin for the Wolves of the Wind. While Sa Enjun believes her loyalty lies with him, she operates as a double agent under Grand Advisor Sho Yosei, the Wolves' true master. After leaving the Hyou clan, her latent powers awakened, granting her clairvoyant abilities termed "Senrigan," enabling her to see over a thousand miles at will. In the second season, auditory hallucinations signal the Hyou clan's renewed efforts to reassert control. Fearing relapse, Shusui attempts suicide. During this crisis, she loses consciousness in Ran Shuuei's arms, inadvertently calling Shouka's name. Shuuei later uses Shouka's name to break her from a hypnotic trance. Resolving to confront the clan directly, Shusui leaves the Imperial Harem for Ran Province. Officially listed as missing, her role is filled by Ran Jyuusan. Returning to the Hyou clan, Hyou Ruka subjects Shusui to the Prison of Time, a labyrinthine dungeon designed to distort perception of time and erode the soul through malevolent spirits. Subjectively enduring this prison for a year, Shusui resists through sheer mental fortitude. This imprisonment is later revealed as the final trial for High Priestess candidates. After Ran Shuuei rescues her, Shusui aids Ruka in eliminating a locust plague and recovering sacred artifacts. She discovers Ruka in deep slumber and encounters the spirit of the first High Priestess, Sou Youki. Ruka then abdicates, entrusting the title of High Priestess to Shusui shortly before her death. Shusui's skills include assassination proficiency from her Assassin Doll training and service with the Wolves of the Wind. She demonstrates exceptional combat abilities, swiftly neutralizing adversaries like the Vice Minister of Arms. Her clairvoyance ("Senrigan") remains a defining supernatural trait. Conversely, she lacks skill in embroidery; Emperor Ryuuki often teases her about this, exemplified when Shouka mistook her embroidered sunflower pattern for a lion. Regarding relationships, Shusui harbors deep affection for Kou Shouka, viewing him as a paternal figure and cherishing his poor-quality tea. Her attachment remains unreciprocated, as Shouka sees her only as an adopted daughter, devoted to his deceased wife. She develops a protective, sisterly bond with Kou Shuurei, Shouka's biological daughter, serving as her lady-in-waiting and later strictly overseeing her health and medication during Shuurei's stay with the Hyou clan. Ran Shuuei experiences love at first sight upon meeting Shusui, though she initially does not recall their encounter. He earns her respect after rescuing her from the Prison of Time. They eventually marry and have three sons, the eldest named Ran Shijaku. Shusui's connection to Hyou Ruka blends maternal elements with conflict. Ruka tested Shusui's resilience through the Prison of Time ordeal, ultimately endorsing her succession as High Priestess. Shusui's lineage ties to the Hyou clan include Hyou Eiki, Ruka's former successor who married Sa Enjun.