Maoujou de Oyasumi S01

In ancient times, when humans and demons coexisted in an uneasy harmony, a demon king took a human princess as a hostage and imprisoned her in his castle. The princess's loyal servants mourned her absence, wailing and lamenting... until a hero emerged to rescue her! But until this champion appeared in his shining armor, what could a captive princess do? The fierce guards with eagle wings were quite formidable, but this captivity was so tedious! It was thus that she decided to spend the long hours of captivity sleeping, if she could find some peace, or escape the insomnia!