Princess Syalis is the main character of the anime series 'Maoujou de Oyasumi' (Sleepy Princess in the Demon Castle). She is a young human princess who has been kidnapped by the Demon King and taken to his castle as a hostage. Despite her predicament, Syalis is more concerned with getting a good night's sleep than with her captivity. Throughout the series, she embarks on various humorous quests within the castle to improve her sleeping conditions, often causing chaos for the demons in her pursuit of comfort. Her character is central to the comedic elements of the show, highlighting her resourcefulness and single-minded determination for sleep.