Reverse/Surface

A pharmacist working at a black company pharmacy is reincarnated into a ruined world of magic for some reason?
He somehow participates in the wizarding examination at the secret organization [Magic Development Bureau] launched by the witch who manages the Millennium Labyrinth discovered in the era of magic's heyday.
This is the story of how he becomes a wizard while making use of his knowledge from his previous life, acquires the mysterious ability [Reverse Surface], and becomes the Magus Lord, the pinnacle of wizards, leading the peace and unification of the magical underworld.