Ku Fei is the twelfth student in class 3-A of Mahora Academy and a transfer student from China. She has blonde hair and green eyes, and her demeanor is almost always energetic, cheerful, and fun-loving, though she can come across as a bit simple-minded due to her lack of academic focus. That academic weakness is real: she consistently places near the bottom of the class, earning her the title of “Baka Yellow” among the so-called Baka Rangers, the five worst-performing students. Her poor grades are largely the result of her still learning Japanese, a language barrier that often leaves her speaking in broken sentences.

Physically, Ku Fei is a prodigy. She is a master of Chinese martial arts, specializing in Xingyi Quan and Bagua Zhang, with additional knowledge of Baji Quan and Xinyi Liuhe Zhang. Her skill is so great that she won the Mahora Academy Martial Arts Tournament, and almost every morning a crowd of challengers gathers to fight her, only for her to dispatch them with ease. She is recognized as one of the school’s top fighters and is grouped with Setsuna Sakurazaki, Kaede Nagase, and Mana Tatsumiya in the informal “3A Martial Arts Elite Four.” Among those four, she is considered the weakest, but only because she relies entirely on pure martial arts without any magic.

Her role in the story expands after the class trip to Kyoto, when Negi Springfield, her teacher, begins training with her daily. They develop a master‑student relationship in which Ku Fei teaches him Chinese martial arts and the instant‑movement technique known as shundou, while Negi’s rapid learning pace amazes her. This connection deepens later: after Negi eventually defeats her in an arm‑wrestling match, she forms a Pactio with him, becoming the tenth student to do so. Her Pactio artifact is an extending pole reminiscent of the legendary staff of Sun Wukong, capable of changing its length and the speed of its extension.

Ku Fei’s motivations are simple and sincere. She is driven by a love of training, a fondness for strong opponents, and an appetite for nikuman, Chinese steamed buns filled with meat. She openly dislikes her classmate Chao Lingshen and the unpredictable inventions of Professor Hakase. Though she starts out as a cheerful battle enthusiast with no knowledge of magic, exposure to the magical world strengthens her ki to otherworldly levels, and her involvement in major conflicts proves that her pure martial spirit can hold its own alongside her magically gifted classmates. Over time, she evolves from a lighthearted brawler into a loyal ally and key teacher to Negi, someone who bridges the gap between traditional combat and the extraordinary events unfolding around her.