According to the official blog, seiyu Hazuki
(formely Tanaka Hazuki) announced that she will resign from the role of Ku Fei
. Asumi Kana
will play the character from Mahou Sensei Negima! Mou Hitotsu no Sekai
episode 4 to be released on August 20th.
Hazuki explained the reason that she will go abroad for a short term studying and will marry soon.
Sources: Hazuki's blog
, Scan of Weekly Shonen Magazine