Empireverse! Nightmare sans x Anarchist! Reader

One King, One Anarchist...

After being caught trying to assassinate King Nightmare of the Moon Empire, Y/N is Captured by the king's henchman.
Y/N knew they could wield magic but Nightmare discovers stronger abilities that Y/N never knew they had.

Y/N swore to never serve a royal, but Nightmare is determined to make Y/N one of his servants...or maybe even his spouse.

This is my first x reader and its not very good.
Updates are slow.
Reader is gender-neutral
TW: Descriptions of injury, mild language, blood, knives, and trauma

Hope you enjoy :D
None of the art is mine