Ryu Kokki (in Japanese: 龍骨鬼, Ryūkotsuki, which translates as Dragon Bone Demon) is the main antagonist and final boss from Getsu Fuuma Den.
Getsu Fuuma Den
During the first years of the Demon Age, the Dragon Master Ryu Kokki was revived in hell by his minions, setting its sights on the human world. In order to protect the world, the two eldest Fuuma brothers go to hell to defeat Ryu Kokki.
However, they end killed and their legendary Wave Sword is stolen, which Ryu Kokki splits in three parts and give to his generals. Getsu Fuuma, the last of the Fuuma brothers, vows to avenge the death of his brothers, venturing into hell to retrieve the Wave Sword and kill Ryu Kokki. Getsu Fuuma defeats the generals and recover the Wave Sword, using its power to defeat Ryu Kokki for good.
Much like many other Konami characters, Ryu Kokki also got his own Yu-Gi-Oh! card, which makes an appearance in Yu-Gi-Oh! GX. He appears as a Zombie Type Effect monster with a Dark Attribute. At the end of the Damage Step, if this card battled a Warrior or Spellcaster-Type monster: Destroy that monster.
- Ryu Kokki appears as a boss in the Getsu Fuuma inspired level of Wai Wai World. He would reappear much time later in the DLC episode "Legend of Getsu Fuuma" from Castlevania Harmony of Despair.
- A female human version of Ryu Kokki appears as a boss in the parody game Otomedius Excellent.