Sleepy Princess in the Demon Castle

Sleepy Princess in the Demon Castle (魔王城でおやすみ) is a Japanese manga series written and illustrated by Kagiji Kumanomata. It has been serialized in Shogakukan's manga magazine Weekly Shōnen Sunday magazine since May 2016, with its chapters collected in twenty-seven  volumes as of March 2024. An anime television series adaptation produced by Doga Kobo aired from October to December 2020.

Plot
The story follows Princess Syalis, a young princess who was kidnapped by the Demon King, and her quest to sleep well while imprisoned. Despite the Demon King's best attempts, the princess turns her kidnapping into a vacation; having grown tired with the stress of a royal life, she is indifferent to the situation.

Characters

 * Princess Syalis (スヤリス姫)
 * Princess Syalis (full name: Aurora Sya Lis Goodereste) (オーロラ・栖夜・リース・カイミーン) is a princess who was kidnapped by the demon king and causes chaos in the demon castle while trying to get a good night's sleep. She has been living at the demon king's castle for four years now.
 * Princess Syalis (full name: Aurora Sya Lis Goodereste) (オーロラ・栖夜・リース・カイミーン) is a princess who was kidnapped by the demon king and causes chaos in the demon castle while trying to get a good night's sleep. She has been living at the demon king's castle for four years now.


 * Twilight the Demon King (魔王タソガレ)


 * Demon Cleric (あくましゅうどうし)


 * Dawner the Hero (勇者アカツキ)
 * Dawner is the hero who is entrusted by the Human Confederation of Goodereste with the task of saving Princess Syalis from the demon castle. Although Dawner and Princess Sylias are childhood friends and also engaged, she does not remember who he is. Whenever she mentions Dawner to the denizens of the demon castle, she calls him, "D-Whatsit". Due to Dawner being outgoing and friendly to Princess Syalis, he had always disturbed her slumber, thus causing her to have nightmares whenever she dreams about him. He is also known for his poor sense of direction, which explains why Princess Syalis has been captured for four years.
 * Dawner is the hero who is entrusted by the Human Confederation of Goodereste with the task of saving Princess Syalis from the demon castle. Although Dawner and Princess Sylias are childhood friends and also engaged, she does not remember who he is. Whenever she mentions Dawner to the denizens of the demon castle, she calls him, "D-Whatsit". Due to Dawner being outgoing and friendly to Princess Syalis, he had always disturbed her slumber, thus causing her to have nightmares whenever she dreams about him. He is also known for his poor sense of direction, which explains why Princess Syalis has been captured for four years.


 * Quilladillo (はりとげマジロ)


 * Frankenzombie (フランケンゾンビ)


 * Minotaur (ミノタウロス)


 * Castle Goblin Grunt (やしき手下ゴブリン)


 * Great Red Siberian (レッドシベリアン・改)
 * Loyal retainer to the Demon Lord, in charge of enforcing rules. The princess drives him batty by her blatant disregard to the fact she's supposed to be a  hostage. In fact, later in the series, he notes that Princess is costing them a fortune with all her misadventures; adding onto the woe everyone endures.
 * Loyal retainer to the Demon Lord, in charge of enforcing rules. The princess drives him batty by her blatant disregard to the fact she's supposed to be a  hostage. In fact, later in the series, he notes that Princess is costing them a fortune with all her misadventures; adding onto the woe everyone endures.


 * Ghost Shroud (おばけふろしき)
 * He and his subordinates are the principal victims of Princess Syralis's antics, especially when she needs cloth to make things to get a good sleep. The death of the Ghost Shrouds by the Princess is a common joke in the series.
 * He and his subordinates are the principal victims of Princess Syralis's antics, especially when she needs cloth to make things to get a good sleep. The death of the Ghost Shrouds by the Princess is a common joke in the series.


 * Poseidon (ポセイドン)
 * A demon who has dominion over water. Because Poseidon never wears a shirt, the princess labels him a nudist.
 * A demon who has dominion over water. Because Poseidon never wears a shirt, the princess labels him a nudist.


 * Fire Venom Dragon (かえんどくりゅう)


 * Neo Alraune (ネオアルラウネ)
 * A gentle plant demon, whom has motherly concern for the Princess. While willing to overlook all the deaths the Cleric is forces to undo, Neo Alraune became "miffed" upon she her tree trunk brother killed by the Princess as part of one her usual ridiculous sleep plans.
 * A gentle plant demon, whom has motherly concern for the Princess. While willing to overlook all the deaths the Cleric is forces to undo, Neo Alraune became "miffed" upon she her tree trunk brother killed by the Princess as part of one her usual ridiculous sleep plans.


 * Alazif (アラージフ)
 * Spirit of a forbidden grimoire the princess freed by sheer dumb luck. Alazif tries encouraging Syalis to use his powers to defeat the demons and leave the castle; however, he is left severely disappointed with her due to her preoccupation with sleeping.
 * Spirit of a forbidden grimoire the princess freed by sheer dumb luck. Alazif tries encouraging Syalis to use his powers to defeat the demons and leave the castle; however, he is left severely disappointed with her due to her preoccupation with sleeping.


 * Scissors Sorcerer (シザーマジシャン)
 * A demon with an arm made of scissors. Syalis gave him her crown to keep his arm together in exchange for his lost scissors; unfortunately leading to her routine of killing the ghost shrouds.
 * A demon with an arm made of scissors. Syalis gave him her crown to keep his arm together in exchange for his lost scissors; unfortunately leading to her routine of killing the ghost shrouds.


 * Harpy (ハーピィ)
 * A harpy who believes that the princess considers her a friend over a misunderstanding with Syalis wishing to nap on Harpy's feathers
 * A harpy who believes that the princess considers her a friend over a misunderstanding with Syalis wishing to nap on Harpy's feathers


 * Hades (ハデス)
 * Twilight's older brother. Unlike his clumsy brother, Hades the classic embodiment of a Demon King; always looking for chance to usurp the throne if Twilight messes up bad enough.
 * Twilight's older brother. Unlike his clumsy brother, Hades the classic embodiment of a Demon King; always looking for chance to usurp the throne if Twilight messes up bad enough.


 * Hypnos (睡魔)
 * A sleep demon; he must sleep 20 hours a day or risk death. Hypnos was called to examine Sylas' nightmare at one point; revealing to the demons just how much the princess loathes Dawner (the source of the nightmare).
 * A sleep demon; he must sleep 20 hours a day or risk death. Hypnos was called to examine Sylas' nightmare at one point; revealing to the demons just how much the princess loathes Dawner (the source of the nightmare).


 * Cubey (さっきゅん)
 * A succubus who looks eerily like the princess; only she has red hair and gold eyes. Cubey wished to learn why the princess was so popular despite looking the same, but got suckered into being trained as her double.
 * A succubus who looks eerily like the princess; only she has red hair and gold eyes. Cubey wished to learn why the princess was so popular despite looking the same, but got suckered into being trained as her double.


 * Queen Nemlis (カイミーンの女王)
 * Nemlis (full name: Aurora Nem Lis Goodereste) (オーロラ・音無（ネム）・リース・カイミーン) is the queen of Goodereste, a kingdom of humankind, and mother of Princess Suyaris.
 * Nemlis (full name: Aurora Nem Lis Goodereste) (オーロラ・音無（ネム）・リース・カイミーン) is the queen of Goodereste, a kingdom of humankind, and mother of Princess Suyaris.

Manga
Written and illustrated by Kagiji Kumanomata, Sleepy Princess in the Demon Castle started in Shogakukan's manga magazine Weekly Shōnen Sunday on May 11, 2016. Shogakukan has collected its chapters into individual volumes. The first volume was released on September 16, 2016. As of March 18, 2024, twenty-seven volumes have been released.

Viz Media announced in September 2017 that they had licensed the series in North America. The first volume was released on June 12, 2018. On May 9, 2023, Viz Media launched their Viz Manga digital manga service, with the series' chapters receiving simultaneous English publication in North America as they are released in Japan.

An official fanbook of the series was released on October 16, 2020.

Anime
An anime television series adaptation was announced in Weekly Shōnen Sunday in September 2019. The series was animated by Doga Kobo and directed by Mitsue Yamazaki, with Yoshiko Nakamura handling series composition and Ai Kikuchi designing the characters. Yukari Hashimoto composed the series' music. The series ran for 12 episodes from October 6 to December 22, 2020, on TV Tokyo, AT-X, and BS TV Tokyo. Inori Minase performed the opening theme "Kaimin! Anmin! Syalist Seikatsu" (快眠！安眠！スヤリスト生活), while ORESAMA performed the ending theme "Gimmme!".

Funimation acquired the series and streamed it on its website in North America and the British Isles. On February 21, 2021, Funimation announced the series would receive an English dub, with the first episode premiering the next day. Following Sony's acquisition of Crunchyroll, the series was moved to Crunchyroll. In Southeast Asia and South Asia, the anime is licensed by Muse Communication, and released on Bilibili in Southeast Asia. The series premiered on Animax Asia on May 12, 2021.

Reception
In 2017, the series was ranked 16th at the third Next Manga Awards in the print category.