Nakabosu-san Level 99, Saikyou no Bukatachi to Tomo ni Nishuume Totsunyuu!

"--This dungeon is useless!"
One day, Ichi Monster Nargoa is appointed as the middle boss of the first dungeon "Shijima Cave" closest to the hero's home base.
There were only unconscious employees (monsters), and Nargoa started a major reform of the dungeon when this was not enough, but it was worth the effort, and even one year after taking office, Shijima's cave was rejected even by a mid-level brave party Transformed into a great labyrinth!
However, the legendary heroes who have already defeated the Demon King, Nargoa challenged and defeated the single heroes to protect their beloved employees, and-somehow reincarnated in the world 100 years later. I will!
In the world 100 years later, a thrilling boss fantasy unfolds with the employees of the Shijima Cave, which has become a legendary labyrinth! Opening here!