Level 1 Demon Lord and One Room Hero manga volume 9 features story and art by Toufu.

After defeating Baphomet, the fearsome drill sergeant of the demonic army, Max and the gang dive head-first into the world of demons. But the Demonic Realm has changed since Max's last sortie during his hero days, and formidable foes stand between him and his objective - the demon lord's castle! This is what happens when you leave your one-room apartment!!