Maou-jou de Oyasumi

A human princess is supposed to be the Demon King's precious hostage, but Syalis treats the demon castle less like a prison and more like a place with terrible sleeping conditions. Surrounded by demons, magic, and dungeon-like rooms, she spends her days hunting for better pillows, softer bedding, and any useful material that might help her rest properly.

Her calm obsession with sleep turns the castle's frightening image upside down. The demons try to guard and manage her, yet they are often dragged into her strange routines, reckless crafting projects, and slapstick trouble. With its playful fantasy setting and cozy sense of routine, the story follows a princess whose greatest enemy is not the Demon King, but a bad night's sleep.