Sleepy Princess in the Demon Castle manga volume 11 features story and art by Kagiji Kumanomata.

Celebrate New Year’s, Valentine’s Day, and a very special pajama party at the Demon Castle with the princess and her demon friends—er, captors! Then the Five Rings athletic tournament captures the imagination of demons and human alike. But when one of the athletes turns the demons’ human friend—er, hostage—into a besotted fangirl, the castle staff doesn’t take it well. Also, Syalis imbibes a potion that induces her greatest fear, Demon King Twilight desperately tries to change his image, and the hero Dawner adds a certain someone to his unwelcome rescue party.