Mui is a magician, who accidentally turned Takeshi into one during her pursuit of her brother, Tsuganashi. This pursuit happened as Tsuganashi was brainwashed by the Ghost Trailer (group of magicians who do not wish to coexist with humans). Mui and Takeshi later formed a good tag team as they work to improve their magic and defend themselves against the Ghost Trailers.
Mui magic power falls under the Acceleration Magic. This magic power allows Mui to create lightning charged attacks, as well as blind her enemy. There are a total of four level types of lightning magic that Mui can cast.