Naofumi was once a successful otaku University student before being summoned to Melromarc. His past experience with Malty Melromarc has made him dark and cynical, but he is still a generally nice person. He has an extremely high alcohol constitution, eating a heavily alcoholic fruit that would cause severe alcohol poisoning if ingested. Although he experiences a slow start because of the Malty incident and is on a much lower level than the other heroes, he is still able to keep up and even occasionally outshine them. Out of the heroes, he is the only one who has learned the written language because he was not given crystal balls to level up his magic abilities and had to learn from books along with Raphtalia. He is also the only one who treated the world as a world and not a game. He has learned to create medicine through recipes and scavenge for materials, something the other heroes left to their weapons. Lastly, he was the only one not killed in his old world before coming to this one.