Nightmare, a villain from the Soul Calibur series, was created from the cursed blade, Soul Edge. (Sword Nightmare holds in right arm.)
The Rise Of Nightmare
Siegfried, a warrior, stumbled upon a ship carrying a large cargo. As he inspected it, he discovered the Soul Edge. As he tried to take it, however, he was attacked by the sword's former pirateweilder and an evil spirit that was gaurding the sword. After defeating them both, he took the sword.
The sword then spoke to him. It told him that it would ressurect Siegfried's dead father if he used the sword to murder people. The sword would devour their souls. Seigfried accepted. After this, he bacame deformed by the Evil Sword's power. He became corrupted. He became Nightmare.
Nightmare went about doing the swords will. After long, though an illusion the sword created appeared to Nightmare. It was an illusion of his father. He told Nightmare that it was all a trick to make the sword powerful once again. Then, the illusion of his father told Nightmare to kill the him. After Nightmare questions this, the illusion demanded he do it. After doing so, Nightmare set out to find redemption for his sins.
Despite this, Nightmare fell to the power of Soul Edge's will...
The Dark Pact
Nightmare became a crazed servant of the sword. To help him gather more souls for the sword, he formed a pact with other villains, including the daughter of the pirate Nightmare fought. Eventually though, they were attacked by several heroes. With no more allies to aid him, Nightmare was defeated and he fell into a chasm.
He regained conciousness. Still alive, he was free from the swords grip for a certain amount of time. Eventually, however, Nightmare fell prisoner to the sword's power once again. He rose to Europe to start another killing spree.
The New Nightmare
Nightmare got into a battle with a swordsman. The swordsman lost, and as Nightmare was about to steal his soul, he stopped. Hesitated. About what he was doing. What he had done. He had enough control of his own mind for him to break free from the will of the Evil Sword. Seigfried reclaimed his body and tossed aside his armor. The holy sword, Soul Calibur came out of the evil Soul Edge. Seigfried used it to attack the evil sword, and both swords became sealed together. Unsatisfied with being one with the good sword, Soul Edge's spirit left and occupied the armor Seigfried threw aside. The armor fled, leaving Seigfried and the swordsman both in shock.
As the armor wandered the land, he was found by the Keeper of Time, Zasamel. Zasalamel created a new body for the Soul Edge spirit out of evil ghosts haunting the area.
Now, this new Nightmare set out in set out after Seigfried and the peices of the now destroyed Soul Edge. He hoped to gain a new body, because this one was somewhat unstable.