You were a demon slayer, killing demons with a small group you had roamed the earth with. You three had been inseparable for years, always having each other's back.

But this, this was just betrayal. They chose you to dress up all fancied and sneak into a party full of sobby rich people.

Y'all were here to kill a demon that had been roaming the city, not expecting to come across another. Which unfortunately was the one you were pared to waltz with. Muzan, the demon king.