There Are No Benefits For The Possessor summary:
Airi, a 10-year experienced professional. Although she awakened her mana, her pitiful talent led her to go into debt for 3 years to learn magic, only to master hand-washing techniques. In the end, her family collapsed and she fell to the status of a maid. As a maid, Airi was locked in the duke’s underground library due to the pranks of the young master. There, she found a sandwich appearing daily, a strange magic circle, and only books. Thus, she was forcibly confined to the Academy of Magic Theories… “When I get out, I’ll sue that kid… No, just let me out.”