Ensei Rou, also known as Ro Ensei, first appears as a disheveled, bear-like figure due to his messy hair and thick beard, causing frequent misidentification as a kidnapper. This prompts Shuurei to insist he shave, revealing a handsome man in his late twenties bearing a distinctive cross-shaped scar below his left eye. His past is marked by tragedy; his entire clan was massacred by the Satsujinzoku gang in Sa Province. He joined the gang during that time, earning the moniker "Little Staff King" for his pole weapon skills, though his true combat mastery lies in close-range unarmed combat, as noted by Shi Seiran. At seventeen, under unprecedented circumstances declared by the Taiho Sa Enjun—that whoever thwarted an assassin would become governor—Ensei was appointed temporary governor of Sa Province. He successfully maintained order and foiled assassination attempts during his tenure. Following Sa Enjun's death, Ensei's legitimacy as governor waned due to diminished political backing. He departed Sa Province to assess Emperor Ryuuki's governance and request a replacement governor. During his journey, he faced repeated attacks from assassins and thieves drawn by a bounty placed on him by the Sa family. He eventually collapsed near Shuurei's estate in Kiyou, where she took him in. After Shuurei's term as Sa Province governor ends, Ensei becomes her assistant in the Censorate, motivated by deep admiration for her ideals and determination. He evolves into her closest confidant, understanding her pragmatic nature and goals better than most, including Seiran. He supports her during critical missions, such as confronting the Jyasenkyou occult and navigating bureaucratic challenges. Their relationship deepens when he helps her overcome a lifelong fear of summer storms, an achievement her family had not managed. She later entrusts him with a key to her awakening during a life-threatening stasis imposed by the Hyou clan, signifying ultimate trust. Ensei shares a complex history with Shi Seiran, rooted in their Satsujinzoku involvement. Their interactions feature mutual irritation, particularly from Seiran, yet underlying respect. Ensei harbors unrequited romantic feelings for Shuurei, largely unspoken and recognized by characters like Shin Suou. His character emphasizes resilience and loyalty. Despite his tragic past, he maintains a gentle, humorous demeanor, serving as both comic relief and emotional support. His journey transitions from provincial governor to dedicated public servant in the capital, reflecting his commitment to Saiunkoku's stability and Shuurei's aspirations.