Dark Dragon (Ninja Gaiden)

The Dark Dragon is a corrupted Dragon God and the main villain of Ninja Gaiden Dragon Sword.

Past
In the ancient time ruled by the Evil Deities, the Deity of Creation gave birth to 13 seeds that took root to become the Dragon Gods. They battled the Evil Deities and banished them from the planet, however the youngest was not as morally strong as the others that could be exploited. Eventually this dragon's feelings of envy and inferiority began to consume him, finally summoning all his hatred and gaining more power through the Archfiend Vigoor. The dragon joined the ranks of the fiends as the Dark Dragon, God of Death and Destruction, biding his time for his strength to grow while assisting Vigoor in devouring the lands of Gurdu. Finally, well into the age of man, the Dark Dragon was at his full power and unleashed his fury, draining the power of the other Dragon Gods, who had been living in peace with the humans. Eventually all his siblings were dead and with the power he had taken from them, Dark Dragon plunged the world into chaos and shadow, even using the devastation and death to spawn his offspring, the Black Dragons. However the other Dragon Gods had created a hope of stopping him in the form of the Dragon Lineage, humans who came to possess items infused with the spirits of the dragons, primarily in the form of the powerful Dragon Sword, created from one of their fangs. Using the sword, the Dragon Lineage slew the Dark Dragon, but upon his death, his essence was transformed into the Dark Dragonstones that scattered across the planet. However it was said that if the stones were brought together, the death dragon would resurrect to envelop the world in death and mayhem. But the fiends discovered a new way to harness the Dark Dragon's power, by taking his bones, they crafted the Dark Dragon Blade. It was an evil sword, powered by the essence of the death dragon and the slain Black Dragons, that acted as sister blade to the Dragon Sword. With the Dark Dragon Blade, the fiends enveloped the world in destruction, until the Dragon Lineage managed to get it, though they were forced to guard it as opposed to destroy it since the only way of doing so had been lost.

Ninja Gaiden Dragon Sword
However the world had not heard the last of the Dark Dragon when Ryu and the fiend sisters, Ishtaros and Nicchae, set out to collect the Dark Dragonstones. The two fiends wanted to bring back Vigoor and his Holy Vigoorian Empire, so as to recreate a world where fiends ruled over man. But Ishtaros and Nicchae needed the Dark Dragonstones, which held the power of the Dark Dragon, in order to do so. They conspired with the Black Spider ninja clan to steal all the relics of the Dragon Gods and even kidnapped Momiji, the shrine maiden guardian of the Dragon Eye. Ishtaros' planned to use the eye, which had fused with Momiji unexpectedly, to manipulate Ryu Hayabusa into killing all who possessed a Dark Dragonstone so that he could gather them for her since each stone called out to each other and thus he would eventually be lead to Ishtaros, who possessed the last. Ryu did exactly as she planned until he finally encountered the fiend sister in the Underworld who stole all the Dark Dragonstones from him to become immensely powerful. But Momiji released the Eye of the Dragon, giving Ryu use of the True Dragon Sword and allowing him to defeat Ishtaros. Nicchae managed to use her sister's body, which was still empowered with the Dark Dragon's power, and used it to resurrect Vigoor. However a cocoon enveloped Ishtaros' body and the Supreme Archfiend lost power, changing to his skeletal, demonic form and was then defeated by Ryu. Nicchae became hopeless as she realized that the age of fiends was unraveling before her and that the Dark Dragon was about to emerge, this time to bring about an age of darkness that would wipe out the humans and the fiends. Nicchae said there was nothing she or Ryu could to do to stop the emergence of the Dark Dragon, but since she was going to die anyway, she could at least take the Dragon Ninja with her. She engaged him a fight to the death only to be slain as the Dark Dragon emerged from the cocoon and attacked Ryu. The death dragon attempting to crush him with his weight and jaws and devastated the area with energy attacks, leaving the Dragon Ninja with almost nowhere to maneuver as the area crumbled. Finally Ryu slew the Dark Dragon before he could escape the Underworld, preventing him from unleashing chaos on the world once more

Personality
The Dark Dragon is the ultimate incarnation of wrath and hate, reveling in mass death and destruction. He only wants to plunge the world into never-ending chaos and shadow, where any living thing is eradicated, be they humans, fauna, and fiends. The Dark Dragon doesn't seem to have any level of loyalty to the fiends despite Vigoor giving him the power to turn on his brethren.

Powers
Due to being a god and the corrupting dark power granted to him by Vigoor, the Dark Dragon possesses incredible power and immortality. He can attack by swooping in on the target so as to crush them under his weight, then devour them and fire energy beams and spheres. The Dark Dragon can not be slain by any weapon except the True Dragon Sword and as a spirit in the Dark Dragon Blade, he can bestow the hatred and evil of all humankind on the wielder, reincarnating them as the "Devil Incarnate". The Dark Dragon's power in the Dark Dragonstones can bring back ruined buildings, entire empires, and even Evil Deities.