Drug-Eating Genius Mage

[By the studio that brought you <Damn Reincarnation> and <Player Who Returned 10,000 Years Later>!]
Having reached his talent limit on magic, the protagonist was sent to the gaming world as punishment — to a huge city named Valkan. In order to survive, he builds relationships with other people and investigates the secret behind the “closed world”, striving to prevent the end of the world.