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OtapediaSleepy Princess in the Demon Castle


Sleepy Princess in the Demon Castle video 1
Sleepy Princess in the Demon Castle video 2

Alternate Titles

Maojo de Oyasumi


Syalis is a cute princess. Like, really cute. And she’s been captured by the Demon King and imprisoned in his castle. How boring! In order to pass the time, she decides to partake in her favorite hobby: sleeping! But getting a good night’s sleep inside a demon castle is harder than it looks, and her demon captors won’t even treat her like royalty. Talk about rude! But no worries, she’ll scheme her way to getting a blissful slumber by any means necessary, like making a pillow out of the fur of her hapless Teddy Demon guards for starters!


Sleepy Princess in the Demon Castle is a manga series written and illustrated by Kagiji Kumanomata that has been serialized in Shogakukan's Weekly Shonen Sunday magazine since May 2016.

An anime adaptation of the series was announced in the 42nd issue of Weekly Shonen Sunday on sale Sep. 18, 2019 and is being produced by Doga Kobo. Staff members include Mitsue Yamazaki as director, Yoshiko Nakamura as series composer, Ai Kikuchi as character designer, and Yukari Hashimoto as music composer. The anime premiered in Japan on Oct. 5, 2020 on TV Tokyo. It is being streamed in North America through Funimation and will run for 12 episodes.


Princess Syalis (Voiced by: Inori Minase)
Princess Syalis is the princess of the unified nation of humankind who was kidnapped by the Demon King Tasogare and became his prisoner. She explores the Demon Castle in search of a good night’s sleep.

Demon King Tasogare (Voiced by: Yoshitsugu Matsuoka)
Ruler of the Demon Castle, Demon King Tasogare kidnapped Princess Syalis in her sleep and hasn’t seen her awake much or talked with her. He is always trying to think of ways to make the hero get to him. Though he tries to act malevolent, deep down he worries about losing.

Demon Cleric (Voiced by: Kaito Ishikawa)
Demon Cleric is in charge of the Demon Temple inside the Demon Castle. He is called upon whenever someone inside the castle needs to be resurrected. He may look like a calm young man but in actuality he is quite old.

The Hero Akatsuki (Voiced by: Hiro Shimono)
Akatsuki is a brave hero who fights to rescue the kidnapped Princess Syalis. He is hot-blooded and straightforward. The princess always forgets his name and that he even exists.

Red Siberian (Voiced by: Chikahiro Kobayashi)
Red Siberian is a demon from the best tribe and one of the Ten Masters who serves the Demon King as his “loyal dog.” He has a strict personality and values discipline. He struggles to make the princess understand that she is a hostage.

**Majiro the Hedgehog ** (Voiced by: Rikiya Koyama)
Majiro works in the Demon Castle as a low-ranking soldier. He is 2 meters tall and looks like a violent person, but he’s actually the type who can’t refuse other people’s requests and has many friends as a result.

**Goblin Serf ** (Voiced by: Shinya Takahashi)
A demon from the spirit tribe, Goblin Serf hangs out with Majiro. He thinks of himself as the most ordinary of ordinary people and doesn’t cause any trouble in the castle. However, he often acts strangely when he takes his clothes off.

Minotaur (Voiced by: Masashi Yamane)
Minotaur is a demon from the beast tribe who has a bull’s head and a strong body. He hangs out with Majiro. His head sprouts flowers when he sees something cute.

Frankenzombie (Voiced by: Koichi Soma)
A demon from the undead tribe, Frankenzombie often hangs around Majiro. Cheerful and laidback, he is tolerant of the princess who often causes a ruckus in the castle.

Teddy Demon (Voiced by: Saori Hayami)
A low-ranking demon who takes care of Princess Syalis, Teddy Demon has a fluffy body made of cotton. He is the type who is vulnerable to temptation and easily gets carried away.

Neo Alraune (Voiced by: Sayaka Ohara)
A demon girl from the plant tribe, Neo is one of the Ten Masters who believes that humans are fundamentally good and feels bad for the kidnapped princess. She is close with her family but worries about her relationship with her useless brother.

Fire Venom Dragon (Voiced by: Takaya Kuroda)
Half-dragon and half-demon, Fire Venom Dragon is one of the Ten Masters and wears a shield around his face to prevent his poison glands from accidently erupting. He battles against Akatsuki.

Poseidon (Voiced by: Takeo Otsuka)
Poseidon is the god of the ocean and one of the Ten Masters. He plays in the water around the castle and often gets into childish fights with the princess. Hades is his brother.

Hades (Voiced by: Kisho Taniyama)
Hades is one of the Ten Masters and Poseidon’s brother. Though he has considerable power, he has a feud with the current Demon King and left the castle to be the lord of Old Demon Castle.

Ghost Shroud (Voiced by: Koichi Soma)
A ghost who dwells in a piece of unused cloth, Ghost Shroud is often targeted by the princess due to his soft and durable material.

Harpy (Voiced by: Sayaka Ohara)
A demon from the wildlife tribe, Harpy can fly and often goes out to scout on the humans. She is interested in human culture and tries to befriend the princess.

Scissors Sorcerer (Voiced by: Junichi Suwabe)
A demon from the machine tribe who can control scissors, Scissors Sorcerer is responsible for giving the princess big scissors that she uses to cut Ghost Shroud. He gets along well with the princess.

Alazif (Voiced by: Ayane Sakura)
The fruits of mankind’s dark wisdom, Alazif is the spirit of a grimoire. Although he has lived a long life, he has a young mental age due to his long slumber. He goes along with the princess’ absurdity out of an obligation to serve the royal family.

Hypnos (Voiced by: Shinichiro Miki)
A demon from the spirit tribe, Hypnos must sleep 20 hours a day or he will die. Because of this, he researches different areas to sleep in and is respected by the princess as a master. He spends his days sleeping in the quiet Old Demon Castle.

Eggplant Seal
A demon from the beast tribe that lives in cold areas, Eggplant Seal’s name comes from the eggplant-shaped protrusion on his head. Due to being cold to the touch, he is often used by the princess as an air conditioner.


  • Opening Theme Song: "Kaimin! Anmin! Syalist Seikatsu" by Inori Minase
  • Ending Theme Song: "Gimmme!" by ORESAMA

International Streaming


Official Info


  • Original Creator: Kagiji Kumanomata
  • Director: Mitsue Yamazaki
  • Assistant Director: Sumie Noro
  • Series Composition: Yoshiko Nakamura
  • Character Design: Ai Kikuchi
  • Sub-Character Design: Chiaki Nakajima
  • Prop Design: Megumi Matsumoto
  • Art Director: Chieko Nakamura
  • Color Design: Kei Ishiguro
  • Director of Photography: Kunihiko Ito
  • Visual Effects: Seiichi Sugiura
  • Graphic Design: Takafumi Kuwano
  • Editing: Mutsumi Takemiya
  • Music: Yukari Hashimoto
  • Music Production: Lantis
  • Sound Effects: Yuika Shiraishi (Iina)
  • Casting Management: Makoto Tanimura (Pro Fit)
  • Animation Production: Doga Kobo

Autumn 2020 Anime