Gekizumi Dungeon Desu ga Skill Hanshoku de Gyakuten Shitai to Omoimasu

After being reborn as a dungeon master in a different world, Akira Hanamura swiftly creates a cozy dungeon in just 30 minutes. However, he soon discovers that his design is a "zero-defense" configuration—exposed to the ongoing stream of adventurers, and if defeated, it means instant death for him. Confronted with this alarming situation, Akira must leverage his exceptional Reproduction skill to increase his monster minions and enhance the dungeon's defenses. With each confrontation, he progressively evolves his modest lair into an impenetrable bastion, employing tactics, forging monster alliances, and adapting quickly to overcome every obstacle.