Okei-chan lives peacefully in a forest with her younger brother Sasuke and animal companions. This tranquility shatters when the demon Yakusha attacks, resulting in the death of one animal friend. Sasuke departs to seek magical training for their protection. During his absence, Prince Yukimura encounters Okei-chan while pursuing the bandit Gonkuro and his allies. A romantic relationship blossoms between Okei-chan and Prince Yukimura during his visits to her woodland sanctuary. After completing his training, Sasuke reunites with Prince Yukimura. Together, they confront Gonkuro's bandits and Yakusha. Okei-chan remains connected to these events through her bond with Prince Yukimura, who allies with Sasuke against the threats to their community.

Okei-chan possesses black hair and brown eyes, reflecting her Japanese heritage. Within the narrative, she primarily serves as Sasuke's sister and Prince Yukimura's love interest.