She Professed Herself Pupil of the Wise Man (Light Novel) Vol. 17

INTRUDER ALERT!
Tasked by Queen Alma of Nirvana to protect the oracle, Mira ends up moving in with the girl. But the evil forces of Ira Muerte aren’t about to sit back and let the oracle keep hampering their criminal goals! When the very castle itself is infiltrated by a mysterious figure seeking to silence a captive before they can spill the beans, chaos ensues, and Mira must jump into action to neutralize the threat.
Series Overview: Sakamori Kagami was one of the top players in the VRMMO Ark Earth Online as Danblf, a veteran summoner with the gravitas to match his elite status.
When he falls asleep playing one day, he’s transported to a world where the game is reality—but instead of his all-powerful avatar, he’s stuck in the body of a cute young girl! He can’t let anyone know that this little cutie is really Danblf, so he takes the name “Mira” and claims to be Danblf’s disciple. If this gets out, he’ll never live it down!