Sleepy Princess in the Demon Castle

Sleepy Princess in the Demon Castle follows a princess who ends up imprisoned inside a demon stronghold after a kidnapping gone awry. Rather than plotting a daring escape, she transforms the situation into a personal retreat, turning the fortress into her cocoon. She curls up with a pillow she sews from a teddy demon guard, catching naps between encounters with the castle's residents. The humor comes from her laser focus on sleep and the comical clashes with the Demon King Tasogare, the Demon Cleric, and other oddball residents who expect a captive princess to scheme, while she longs for another nap. The tone stays light and playful, filled with cute moments that keep the pace brisk.

Released in 2020, this is an original anime conceived by Yoshiko Nakamura. It features Inori Minase as Syalis and a voice cast that includes Kaito Ishikawa, Yoshitsugu Matsuoka, Hiro Shimono, and Rikiya Koyama.

Audiences have responded warmly, shown by an 8.4 out of 10 average from 131 votes. The show earns praise for its breezy humor, charming cast banter, and gentle fantasy vibe that blends light sci fi touches with comfort driven storytelling.