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GetsuFumaDen Wiki
For other uses, see Ryukotsuki (disambiguation).

An evil spirit was sealed away by the first Getsu Fuma a thousand years past. It was the beginning of the long-standing connection between the Getsu clan and hell. Now that the Ryukotsuki has been revived, hell's specters pour from the giant chasm.
~ Official description from Undying Moon

Ryukotsuki (龍骨鬼 Ryūkotsuki?, lit: "Dragon Bone Demon") is the main antagonist and final boss of the 1987 Famicom game GetsuFumaDen. A powerful Demon Lord, they escaped from Hell and sought to conquer the surface world.


In 14672 A.D., the first year of the "Demon Age", the Demon Lord Ryukotsuki escaped from hell and plotted to conquer the surface world ruled by the three Getsu brothers. The siblings courageously fought against her, each wielding one of the three spiritual Hadou katanas that had been passed within the clan for generations. However, the brothers were ultimately defeated by the demoness and only Fuma, the youngest of the three, survived.

Vowing to avenge his slain brothers, Fuma ventured into the island of Raging Demon –where Ryukotsuki and their lieutenants, the loyal Majins, resided– and recovered the three stolen Hadou katanas, with which he ultimately defeated Ryukotsuki, destroyed the Demon Lord's castle, and sealed the evil away.

A thousand years later, the seal became unstable and Ryukotsuki was once again free to attempt to invade from hell, leaving it up to the current Getsu Fuma, descendant of the original and 27th leader of the Getsu Clan, to deal with the raging demon this time.

Gender ambiguity[]

The instruction booklet of GetsuFumaDen refers to Ryukotsuki as Maō (魔王?), which translates as "Demon Lord"; however, this term can be applied to both male and female characters when translated to English. The instruction booklet and most other media otherwise avoids the use of any gendered terms for Ryukotsuki.

Due to the limited information contained in the instruction booklet of GetsuFumaDen, as well as the particular interpretations of the character in various crossover and cameo games they have also appeared in, that portray the Demon Lord as female, there exists some confusion as to Ryukotsuki's gender. As these spinoff appearances are of questionable canonicity, the question of Ryukotsuki's gender remains unclear.


First appearance of Ryukotsuki in any media. They act as the main antagonist and final boss of the game.

After Fuma defeated the loyal Majins, with whom Ryukotsuki left the three Hadou katanas that had been stolen from the Getsu brothers to guard them, the Getsu warrior challenges the Demon Lord to a final battle in the innermost sanctum of their castle in Raging Demon Island.


Ryukotsuki's boss fight consists of three phases:

Phase 1

Ryukotsuki appears in the form of decrepit horned skeletal shade wrapped in ceremonial robes, reminiscent of traditional hannya demon folklore. This form only attacks by hopping forward a few times and then stopping to expel a large fireball from their mouth. This first phase is not very resilient, though, and can be quickly subdued with the power of the Hadou katana.

Phase 2

In the second phase of the battle, Ryukotsuki adopts a more youthful form, taller and fashioning long red hair and sporting a horn reminiscent of an Oni demon. Their most notorious asset during this phase of the fight is the metal shield they carry, which can deflect the energy waves of the Hadou katana. The Demon Lord switches defense from high to low depending on the player's attacks, and from the current unguarded area they throw sai straightforward, all of this while slowly advancing forward in an attempt to corner the hero. The player must aim the trajectory of their attacks properly in order to hit the area of Ryukotsuki's body that is unguarded at that moment. If cornered, charge at them and jump over to the other side.

Phase 3

Ryukotsuki's last form, making good on the meaning of their name, adopts the monstrous form of a large dragon demon whose body is composed entirely of bones and whose limbs, both upper and lower, are made of skulls. The beast attacks by menacingly advancing forward and swiping at the ground with a clawed hand; all of this while consistently spewing three fireballs downward in a spreading manner. A large red core can be seen within the exposed rib cage, which acts as their weak point. Aim the energy waves of the Hadou katana at it, while keeping a safe distance and evading attacks as necessary until the demon dies.

Once Ryukotsuki is defeated, Fuma uses the three Hadou katanas to summon the spirits of his two older brothers and altogether the three siblings conjure the secret technique of the Dainendōha, which seals Ryukotsuki's evil spirit and calls upon a bolt of lightning from the sky which destroys the Demon Lord's lair.

GetsuFumaDen: Undying Moon[]

1000 years after the first game, Ryukotsuki manages to break the seal cast upon him by the original Fuma, releasing with this hordes of demons that invade the surface world. However, the Getsu Clan have been vigilant all this time in case something like this could happen. A new hero stands up to the challenge, bearing the same name of the legendary hero that a millennium ago succeeded in defeating the Demon Lord: Getsu Fuma.


Ryukotsuki's Undying Moon boss fight consists of two phases:

Phase 1

Ryukotsuki has a number of attacks they will execute in this phase:

  • Pulling back their left arm and swiping forward all the way to the left edge of the screen. This can be avoided by hugging the far left wall, or just by performing a roll at the right time.
  • Raising up their right arm before pounding down on the ground. This tracks roughly tracks the player, and has a bit of a splash damage zone, but can be avoided by running out of the way as the descent begins.
  • Rearing up and summoning smaller skulls that slowly descend upon the player. These can be destroyed with a simple attack.
  • Rearing up and gathering power before vomiting forth a giant ball of flame at the player. This will target where the player was standing when Ryukotsuki launched the fireball, and can be avoided by getting out of the way.
Phase 2

After Ryukotsuki has lost roughly half their health, their flames will turn from blue to purple and green, and their attacks will be powered up.

  • The swipe with the left hand is now quicker to execute than it was in Phase 1.
  • The pound with the right fist now has a much larger splash damage zone.
  • The summoned skulls are now faster and more numerous.
  • The fireball now sends out a wave of pillars of flame to both sides, spreading out from where it touched down. Time a jump over these properly to avoid them.

Ryukotsuki has many hurt zones that can be damaged, but their hands have individual life bars separate from Ryukotsuki's main body. If both hands are depleted, Ryukotsuki will be staggered, allowing for a Slay attack for massive damage. Afterward, both hands will respawn.

Destroying a hand will inflict a flinch, interrupting an attack, and is good for getting out of tight situations if the need arises.

Other appearances[]

Konami Wai Wai World[]

Ryukotsuki appears at the end of the GetsuFumaDen-inspired stage as the main boss. This game sports a more draconic appearance than that in the original game, although keeping most of the characteristic features: a huge demon made entirely of bones and with limbs conformed by skulls, swipes with giant claws in front, and has an exposed weak point within the open rib cage. This appearance is closer to how Ryukotsuki was depicted in supplemental materials for GetsuFumaDen, such as the Winning Perfect Book and the Adventure Game Book.

While Ryukotsuki only appears in dragon bone demon form, one of their attacks is releasing smaller Ryukotsuki Junior enemies to aid in the fight against the player. Both official Wai Wai World strategy guides outright call Ryukotsuki a "mother" to these smaller enemies, naming the demon "マザー龍骨鬼", or "Mother Ryukotsuki". If allowed, Ryukotsuki can fill the area with offspring in a short time, making it difficult for the player to maneuver among the myriad of fireballs filling the screen.

Wai Wai World 2[]

Ryukotsuki returns in the sequel to Konami Wai Wai World, once again as the boss to the GetsuFumaDen-themed stage. This time, Ryukotsuki's appearance is that of a traditionally muscular male body (but with a dragon's head). This Kinniku Ryukotsuki (筋肉龍骨鬼 (きんにくりゅうこつき)?, "Muscle Ryukotsuki") attacks by running back and forth across the arena and occasionally spewing out fire that will cover an area for a short time.


Ryukotsuki also appeared as a card in Yu-Gi-Oh! called Ryu Kokki, along with Getsu Fuhma. Both character appear battling each other on the Fuhma Wave card.

Pop'n music 18: Sengoku Retsuden[]

The climactic battle between Getsu Fuma and Ryukotsuki is played out in this title in the form of a rhythm game.

Castlevania: Harmony of Despair[]

Ryukotsuki appears as the main boss in Harmony of Despair's DLC chapter, The Legend of Fuma. They reprise their three different forms from the original:

  1. In the first form, Ryukotsuki is just a regular-sized cloaked enemy wearing a horned skull mask. They attack by shooting fireballs and jumping at the heroes from time to time.
  2. The second form is a tall warrior with long red hair and heavy armor which wields a shield and attacks by throwing sai at the heroes.
  3. In the third and final form, Ryukotsuki transforms into a gigantic dragon-like demon conformed by different kinds of bones, with arms and legs made up of several skulls. A red orb is encased inside their thoracic cage and serves as the monster's weak spot, although it's impervious to most forms of attack. The Demon Lord attacks by summoning a series of swords to rain on the heroes, by swiping with their claws, by shooting three bouncing fireballs from her mouth, and by summoning Ryūtōkibi to attack the players. The beast's humongous size can also be considered as a form of attack, as they'll advance toward the heroes, reducing their area to maneuver.

Otomedius Excellent[]

Main article: Ryukotsuki (Otomedius)

Ryukotsuki appears in the 2011 Xbox 360 horizontal-scrolling shooter game Otomedius Excellent, alongside with Gesshi Hanafuuma, a female member of the Getsu Clan, and other characters from or representative of various other Konami franchises. Ryukotsuki's appearance is based on the second form from GetsuFumaDen, and is distinctly female in this game.

Other media[]




  • Takiyasha the Witch and the Skeleton Spectre, a woodblock in the ukiyo-e style by Utagawa Kuniyoshi (c. 1844).

    Ryukotsuki's updated redesign for GetsuFumaDen: Undying Moon appears to be inspired by the Gashadokuro, which are spirits in Japanese mythology that take the form of giant skeletons that are fifteen times taller than an average person, and which roam after midnight, preying on lone travelers whom they grab and bite their heads off to drink their spraying blood.
  • Ryukotsuki's original design, as well as most following depictions in other media, portray them having a red core (that is, a red gem-like sphere) within their rib cage; however, the redesign in Undying Moon portrays it as their exposed heart.
  • Homusubi Specter from Sakuna of Rice and Ruin.

    Studio Edelweiss devs have stated that the Homusubi Specter of Sakuna of Rice and Ruin was inspired by Ryukotsuki, the development team being fans of GetsuFumaDen.[1]
  • Also in Undying Moon, the Demon Lord is described as "The Ryukotsuki", similar to Ganon's treatment as "The Calamity Ganon" in The Legend of Zelda: Breath of the Wild.
  • Ryukotsuki may possibly be inspired by Baigujing (白骨精 Báigǔjīng?), a demon from the 16th century Chinese novel Journey to the West. The name is translated into English as White Bone Spirit in the William John Francis Jenner translation. Baigujing is a shapeshifting demoness, and in her true form she is depicted as a skeleton. In most translations and adaptations she has a feminine human form and a monstrous skeletal form sporting a red core. She tried to trick the party by turning into a beautiful woman to eat the monk Tang Sanzang, whose flesh was rumored to grant immortality. The monkey king Sun Wukong saw through her disguise on multiple occasions, finally revealing her true skeletal form and defeating her once and for all.
  • Baigujing bears some resemblance to the Japanese folklore surrounding the hannya demons, in that she is implied to have been a human woman driven to demonhood after death. In turn, Ryukotsuki's three forms in GetsuFumaDen also bare some parallels to the three grades of hannyahannya: namanari, chūnari, and honnari. Namanari hannya are kijo that still resemble human women that have small horns and use dark magic to perform their evil deeds. Chūnari hannya are mid-level demons that have long, sharp horns, tusk-like fangs, and more powerful magic. Honnari hannya are true demons and the most powerful of the three, having serpentine bodies and breathing fire.

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