Ku Fei is a Chinese exchange student in Mahora Academy's Class 2/3-A. Her darker skin tone suggests origins from a different region of China. She stands 151 cm tall, weighs 71.3 kg, and sports blonde hair in spiky twin tails alongside green eyes. Her Japanese speech frequently adds the suffix "aru," reflecting her native language background and ongoing fluency struggles. This contributes to her academic challenges and membership in the remedial "Baka Rangers" as "Baka Yellow." Trained in Chinese martial arts, Ku Fei specializes in Xingyi Quan and Bagua Zhang, with knowledge of Baji Quan and Xinyi Liuhe Zhang. Within her class, she ranks as the fourth strongest combatant, behind Setsuna Sakurazaki, Mana Tatsumiya, and Kaede Nagase. This ranking results from her lack of magic; she relies solely on physical prowess and ki control. Mana Tatsumiya states Ku Fei is "the strongest normal human" in pure martial skill and brute strength. She won Mahora Academy's martial arts tournament the year before the series begins and defends her title daily. Her athleticism extends beyond combat, demonstrated by bowling a perfect 300 game on her first attempt. Outside academics, she works at Chao Lingshen's Chao Bao Zi restaurant, developing an obsession with nikuman meat buns. This friendship leads her to serve as an involuntary test subject for Chao and Satomi Hakase's inventions. During the Kyoto class trip, she participates in a contest to kiss Negi Springfield, resulting in an incomplete Pactio contract via a paper clone. She later learns Negi's magical identity during Konoka Konoe's rescue and becomes his martial arts instructor. Adopting the persona "Ku Roshi" (Master Ku), she teaches Negi foundational combat skills and ki manipulation, enabling him to master techniques like shundou (instant movement) in reduced timeframes. Ku Fei forms a formal Pactio contract with Negi in the Magic World arc, receiving the artifact "Pugilatum Exercens" (To Train the Fists), later revealed as a replica of the Ruyi Jingu Bang staff from *Journey to the West* that changes size at will. She joins Negi's Ala Alba (White Wing) group traveling to the Magic World. Their team scatters after an ambush by Fate Averruncus. Surviving independently, Ku Fei works as a bodyguard-for-hire and hones her combat skills by breaking rock pillars. During this period, she demonstrates enhanced abilities, firing potent ki beams capable of nearly blindsiding opponents like Fate. In the Mahora Festival arc, she prioritizes defending her martial arts title, defeating Mana Tatsumiya in a grueling match that breaks her left arm. The injury forces her withdrawal, though Albireo Imma later heals it. Despite her close friendship with Chao Lingshen, Chao conceals her time-traveling mission, leading to an emotional farewell. During the festival's climactic battle, Ku Fei fights Chao's robotic Chachamaru clones to protect Mahora. Ku Fei appears in *Mahō Sensei Negima! Anime Final*, which adapts events following the Magic World rescue. The film centers on Negi selecting a permanent Pactio partner before the class's memories of magic are erased, with Ku Fei participating in graduation preparations.