Sakimori Kagami is a player of the VRMMORPG Ark Earth Online and is the foremost expert in the area of Summoning Magic. His Character, Dunbalf Ganadore is considered one of the expert class players who stands at the height of magic. After putting a lot of effort into using a cash item called the Vanity Case, he accidentally turned his character into a little girl. This just happened to be when he was brought into the Second World where Ark Earth Online became the reality. Forcing him to profess herself as the disciple of the Wiseman to hide his identity.

(Source: She Professed Herself Pupil of the Wise Man Wiki)