Drug-Eating Genius Mage

Briefly about Drug-Eating Genius Mage manga:

Having reached the limit of his magical abilities, the protagonist was sent as punishment to the game world, to a huge city called Valkan.

Drug-Eating Genius Mage manga.

To survive, he builds relationships with other people and unravels the mystery of the “closed world” in an effort to prevent the end of the world.