Boushoku-Hi no Ken

A low-level adventurer named Dean is cornered by demonic creatures inside a labyrinth and escapes by finding a powerful sword known as Belzera, created by the Gluttony Empress Belzebuth. The sword consumes power and is considered the strongest among demons. With this newfound strength, Dean seeks to become a top-tier adventurer and continues his journey deeper into the labyrinth.