Yumei has twon buns one each side of her head and a small ponytail sticking next to the right side bun. She has an emotionless face and blue hair. She has rather thick eyebrows, and a young-looking face.
Yumei was originally a low-level fox "born on the streets." Upon meeting Ha-Eun, he gave her a personality but as side-effects she is unable to have any facial expressions.
Yumei is introduced as a mysterious girl that vists Yu-Da. She is revealed to be a companion of Ha-Eun, and often does tasks for him, such as finding him a new vessel and collecting low-level foxes. She is seen to also handle Mi-Woo when Ha-Eun isn't around. Later in the series, she suggests that she likes Yu-Da by telling him "when I look at you, my heart wants to smile," and that he is the most important person (along with Ha-Eun) to her.