Sleepy Princess in the Demon Castle manga volume 5 features story and art by Kagiji Kumanomata.

Princess Syalis comes to the surprising conclusion that being good will earn her a good night’s sleep! But none of the demons trust her sudden transformation. The princess’s latest dilemmas include a growing urge to use the bathroom when it’s out of order, her pet Eggplant Seal outgrowing her quarters, and growing into a giant instead of up. And then it’s time for the castle’s Hostage Reeducation Week… Plus, a visit to demon preschool!