Kono Kamen no Akuma ni Soudan wo!

Synopsis

After Wiz wastes all the money Vanir made from Kazuma's patents on high quality Manatite, Vanir is forced to take up a job in consulting to pay the monthly rent of the shop. Aqua couldn't fall asleep, and decided to invade Wiz's shop to inquire about her and Vanir’s past. Various characters consult Vanir for help. (Source: MangaDex)