The book version is currently being published by K Kodansha Novels! Additionally, a manga adaptation has started serialization on Niconico Seiga. I would be delighted if you could read it. The first volume of the manga will be released on 10/9! -- Even though a small room would have been enough, what ended up being created was a vast and powerful dungeon. Chrono, an ordinary demon, creates a dungeon at the Demon King's Castle Academy. It is a custom among demons to create a dungeon at the Demon King's Castle when they turn twenty, live there, and study to become independent. Chrono thought a small dungeon would suffice, but what he ended up creating was a massive structure spanning hundreds of floors. It was so powerful that it surpassed the dungeons created by legendary Demon Kings. 'I just wanted a small dungeon...!' Chrono, who desired a simple and easy life, quickly became the center of attention and rose through the ranks of the demon world. Eventually, he was even called a hero.