Kuka is an elderly sage and former retainer of the Takemikazuchi royal house. He once served as the personal bodyguard to Yuki's mother, Azora, long before the clan's leadership was seized by Byakurai. Living in seclusion in a forest, Kuka reemerges to meet Yuki and reveals the truth about her heritage and the circumstances of her mother's death. He tells her that Byakurai murdered Azora to prevent Yuki from ascending to her rightful position. This revelation triggers Yuki's decision to leave the clan and seek vengeance.

Kuka is portrayed as a calm, wise figure carrying the burden of long-hidden secrets. His loyalty to the legitimate bloodline and his sense of duty drive him to seek out Yuki despite the danger. He is not physically formidable in his advanced age, but he possesses a quiet resolve and a willingness to sacrifice himself for the truth. During their encounter, the Takemikazuchi launch an ambush. Kuka fights to protect Yuki but ultimately perishes in the battle, dying as he ensures that the critical information is passed on. His role is that of a catalyst, providing the protagonist with the knowledge that sets her on a new path. He remains a one-scene mentor figure whose courage and loyalty leave a decisive mark on the story.