Manga Self-Proclaimed Ordinary Demon's Heroic Life: The Result of Him Creating a Cheat Dungeon, Even Though He's Supposedly a B-Grade Demon

The events of this story will unfold in the academy of demons and dungeons. In this world, all demon boys, when they turn 20, go to the demon academy, where they begin to study the basics of magic, dungeons and other demonic things. The protagonist of the story is a guy named Chrono Arkon, who just belongs to this category of young people. Although it is difficult to call him a truly dangerous creature, since everyone here is holding him for a fool. However, Chrono's life will change dramatically after a serious incident on the very first day of the academy. He managed to create a dungeon with 400 levels! Now he will go to explore it together with a pretty vampire girl and other unusual allies.