Kuu Fei is a student in class 3-A at Mahora Academy, known for her energetic and cheerful personality. She is a Chinese exchange student whose native language is Chinese, and she is still learning Japanese, which contributes to her academic difficulties. Her hair is blonde and her eyes are green, and she is often seen wearing her school uniform while maintaining an enthusiastic and playful demeanor. She has a fondness for meat buns called nikuman and openly dislikes complex inventions created by her classmate Chao.

Her greatest strength lies in martial arts. Kuu Fei is an exceptionally skilled practitioner of Chinese styles, specializing in Xingyi Quan and Bagua Zhang. She also possesses knowledge of Baji Quan and Xinyi Liuhe Zhang. Her combat proficiency earned her victory in the Mahora Academy Martial Arts Tournament, after which challengers routinely sought her out every morning, and she fended them off with ease. She is recognized as a member of the school’s martial arts elite four, alongside Setsuna, Kaede, and Mana. Although among that group she is considered the weakest when fighting without holding back—because she relies purely on physical martial arts rather than magic—she remains one of the most dangerous students in the class.

Academically, she ranks near the bottom and is given the nickname Baka Yellow as part of the group of the five lowest-performing students. Her poor grades are largely a result of her ongoing struggle with the Japanese language, not a lack of intelligence or effort. Despite this, she is sharp in combat and shows a thoughtful side when teaching or analyzing fights.

In the story, her role expands after a class trip to Kyoto, when Negi Springfield, the young teacher, begins training with her daily. They develop a mutual master-student relationship: Kuu Fei teaches him Chinese kenpo, and he absorbs the techniques with remarkable speed. This bond grows stronger as the series progresses, and she becomes one of his trusted allies. In a later chapter, she forms a Pactio contract with Negi after he defeats her in an arm-wrestling match. Through this magical contract, she receives an artifact: a red extending pole that can change its length and the speed of its extension, evocative of the staff wielded by the legendary Sun Wukong.

Kuu Fei’s motivations center on her love of training, her respect for strong opponents, and her loyalty to her teacher and classmates. She consistently seeks to improve herself and protect those around her. Her development moves from being a cheerful, brawling tournament champion to a dedicated teacher to Negi and a vital member of his network of allies. She maintains a warm, friendly rapport with the other martial arts students and brings a straightforward, uncomplicated joy to every battle and interaction.