A world where the Demon King has been defeated and peace has been restored. Adventurers running around the world. However, the Demon King was not destroyed! The Demon King, who has acquired a mysterious power called "bug" that is different from magic and skills, hides in the depths of the dungeon with his few confidants and sharpens his fangs of revenge! Use the power of unconventional "bugs" to set invisible traps in dungeons, turn adventurers into monsters, and aim to expand your army!