Kokū is a lady-in-waiting in the Jade Pavilion who serves Consort Gyokuyou, a high-ranking concubine of the Emperor. She is a minor character in the narrative. Kokū entered Gyokuyou's service prior to the birth of the Crown Prince and serves alongside her sisters: Haku-u, her older sister, and Seki-u, her younger sister. The three siblings form the core of the consort's small, trusted staff. In her role, Kokū assists with the daily management of the consort's household, tending to the needs of Gyokuyou and her children. Her character is defined by her loyalty and her consistent, unassuming presence within the Jade Pavilion. As a member of this household, she interacts regularly with her fellow attendants, including the series' main character, Maomao. Kokū does not possess any specialized or notable abilities beyond the expected duties of a dedicated lady-in-waiting. Her role in the story remains a background one, providing support and stability to the consort's residence without undergoing any significant personal development or taking part in the central mysteries of the palace.