Days as a Butler in the Monster King’s Household

After the war between humans and monsters ended, the seven strongest human mages erected a barrier and sealed the monsters underground. Kato, the first monster to be born naturally after the sealing, was found by Gerson. Together, they went to their “new home” to witness the king's speech.

“It's your turn, Mr. Fuzzball!” the queen teased the king after his speech. But she forgot to turn off the microphone. “You say you were born naturally? But according to our theory, monsters can't be born naturally at all.” In the laboratory, the Skeleton Brothers eyed the cat and turtle before them suspiciously.

And now, their peaceful everyday life was about to be shattered by a human falling from the sky...

This is an Undertale fanfic with an ensemble cast. The male lead isn't invincible, and it contains plenty of original fan-created content. Readers who aren't familiar with the original work can still enjoy it!