Nightmare (Soul Calibur)

Nightmare is the physical manifestation of the Evil Sword Soul Edge, and a major antagonist in the Soul Calibur video game series.

Nightmare was originally created as the alter-ego of Siegfried Schtauffen, created when he got hold of Soul Edge and was consumed by the sword's will, during which time he wore dark blue armour that earned him the nickname "the Azure Knight", and went by the name "Nightmare".

Since Siegfried managed to free himself from the evil blade's influence, it has somehow formed an entirely new being, an avatar of darkness, instead of possessing a new host. This new being models himself after what he looked when possessing Siegfried. This new Nightmare, like the original, uses a great blade in battle, though his moves are unique, differentiating him from his human predecessor.

Nightmare is also referred to as the Symbol of Destruction.

Pre-Soul series
Soul Edge was once a blade wielded by the Hero King Algol, but after being stained by Blood it grew a wicked soul. No matter how hard it tried it could not take over Algol as his will was too strong, one day Algol's son Arcturus touched Soul Edge and was controlled, Algol was forced to kill his son. Algol then created Soul Calibur from a shard of Soul Edge and sealed the blades away.

Soul Blade (Soul Edge)
In the 16th Century, Rock's father purchased Soul Edge at an auction, but his ship was attacked by Cervantes de Leon, upon discovering Soul Edge, Cervantes was possessed by Inferno.

Cervantes (possessed by Inferno) owned the sword for two decades, many ventured to the port where Cervantes lived and he killed them all, absorbing their souls until Sophita came and confronted him, Sophitia managed to destroy the smaller Soul Edge but was defeated by Inferno-Cervantes, until Taki arrived and managed to defeat Inferno-Cervantes.

A young warrior named Siegfried discovered Soul Edge, and Inferno realising Cervantes was useless engaged Siegfried in battle to possess him, but Siegfried managed to defeat Inferno, though the victory was still Inferno's as Siegfried touched Soul Edge and was possessed, trasnforming him into Nightmare (also known as Siegfried!)

Soulcalibur
in Soulcalibur, the concept was expanded and turned into an official character, though with changes to the design. His red armour was changed to a dark blue one, thus his nickname of "Azure Knight", and its design turned more metallic instead of flesh. This was also the first appearance of the Malfested Arm; Siegfried's body was slowly being mutated by the sword's terrible power, most dramatically his right arm had transformed into a vicious, hard-shelled claw. Despite the Malfested Arm only having three large fingers, it didn't seem to hinder his combat abilities at all. He now wields his own version of Soul Edge, sporting a single eye on its blade, something that would become the trademark of the various versions of the weapon, and the creations made from it, such as Charade.

Nightmare was a starting character whose style resembled Siegfried's former style upgraded. Siegfried was later added to the cast as a time-release character, and inherited the same style with minor changes and speed and weight differences. Nightmare's profile on the game explained how Siegfried obtained Soul Edge after a fierce fight against its former owner, the dread pirate Cervantes de Leon, and the firey demon that spawned within it afterward, Inferno. After that, the sword spoke to him, promising the resurrection of his dead father if he helped it gather souls. Unaware that it was a trick of the sword to restore his power, Siegfried agreed and started a killing spree, which eventually drove him to be fully possessed, taking the name "Nightmare" and spreading chaos on the lands.

Soulcalibur II
Nightmare's incarnation on Soulcalibur II remains mostly the same, with minimal upgrades to his fighting style, mainly on his stance game. Story-wise, as his and other characters profiles explain, he formed a group with Astaroth, Isabella "Ivy" Valentine (who did not realize that Nightmare's sword was Soul Edge, which she sought to destroy), and Aeon Calcos, the Lizardman, in an attempt to speed the gathering of souls and restoration of the sword's power. But during the ritual to restore Soul Edge, his castle, Osthreinsburg, was assaulted by Kilik, Maxi, and Chai Xianghua. With his allies either defeated or missing, Nightmare confronted Kilik and Xianghua and was ultimately defeated, later falling into the collapsing void where they fought. After waking up, Siegfried, apparently free, regained his senses and tried to distance himself from the world to atone for the sins he committed and the death of his father. But the sword slowly regained control over the young man, and eventually Nightmare resurfaced to start another massacre on Europe. In this game, Nightmare is a starting character, while Siegfried turned into a third costume option for him. In his second costume option, which bares his chest and head, it can be seen that most of the right side of Siegfried's chest has been corrupted in a similar manner to his arm, and his right eye has changed to a golden colour.

Soulcalibur III
Due to his defeat by Raphael and Siegfried in Soul Calibur II, Soul Edge lost his host, Inferno desperatley tried to raise his armor but failed, until Eventually the mysterious immortal Zasalamel found him and used his powers to allow Soul Edge to take control of the armor once more, becoming Nightmare again. Since Siegfriend had stolen Soul Edge (now fused with Soul Calibur as Soul Embrace) Nightmare was weakened and was forced to use a shards of Soul Edge to recreate the sword. Nightmare restarted his reign of terror in search of Siegfried and to get Soul Edge.

Soulcalibur IV
The corruption of Nightmare's body was more accelerated because the body had no soul to resist the dark influence. By this time, Nightmare's entire body had been twisted by the power of Soul Edge; one costume is clearly inhuman, the entire midsection missing, pure dark energy taking the place of flesh and bone, the other depicts a supremely mutated torso, the eyes glowing red, the skin gnarled and black, glowing veins running throughout.

As the storyline of this game begins, Nightmare and Siegfried found each other once more at the Lost Cathedral. Soul Edge was freed from the Soul Embrace because of a secret art performed by Zasalamel. Nightmare took the evil sword while Siegfried became the new wielder of Soul Calibur. Then the two fought, and the clashing of their swords created a very powerful explosion that destroyed the cathedral.

Both Nightmare and the evil sword then fell into some sort of dimensional warp. Conveniently, they both landed in Ostrheinsburg. Waves caused by the clash of the two swords awakened the fragments of Soul Edge that were scattered all over the world. They flew to Ostrheinsburg, and the evil sword consumed all of them, regaining its true power. As Nightmare made roots into the land, Ostrheinsburg soon became a cursed city, which Nightmare can use to devour souls. The Azure Knight then waited for Soul Calibur to come so he could destroy it once and for all.

The storylines involving Algol feature a different storyline in which Algol, the ancient king whose will was strong enough to totally resist Soul Edge's power, and who created Soul Calibur in case Soul Edge ever needed to be destroyed, somehow gets his hands on both spirit swords, wielding them simultaneously as he plots his resurrection and return to his post as king of the world. It can be assumed that in order to accomplish this he defeated both Nightmare and Siegfried.

Soulcalibur V
Nightmare returns in Soulcalibur V, after the Azure Knight's defeat by Siegfried in the previous game he gained a new host named Graf Dumas (implied to be Raphael). Nightmare allied himself with the king and began making an army of Malfested, he also gained an apprentice named Patroklos Alexander and used him to get more Souls by getting him to kill normal people (claiming they were Malfested).

Eventually Patrokolos realizes his betrayal and confronts Nightmare, though Nightmare leaves and forces Patrokolos to fight Voldo. Nightmare later confronts Patrokolos in order to kill him and defeats him, but Pyrrha's rage allows her to transform into a malfested and she manages to wound him, Nightmare then leaves while Pyhrra checks on Patrokolos.

Nightmare and his malfested warriors attack most of Europe and engage in a huge battle with Siegfried and his army. Siegfried tells Z.W.E.I. to go after Nightmare. At Castle Denevér, Nightmare begins his final battle with Z.W.E.I. but is defeated by him and knocked of the edge. Immediatly after the death of Graf Dumas, Pyrrah is led by Tira to Z.W.E.I. and Pyrrah stabs him and knocks him off the cliff, Pyrrah then picks up Soul Edge and is possesed, becoming Pyrrah Omega.

Pyrrah Omega is the confronted by Patroklos (now Alpha Patroklos), Patroklos fights Pyrrha and defeats her, he is then fully taken control of by Elysium and he kills his sister. Patroklos then realises that Elysium is not his mother and uses his power to travel back in time, he then confronts Pyrrah and defeats her, he is the forced into a mental battle with Elysium. Pyrrah uses Soul Edge to free her brother and they stab Soul Edge into Soul Calibur, leaving the swords fate unknown.

Personality
Nightmare has been portrayed in the games as a violent and ruthless creature, constantly in search of souls to restore Soul Edge. He looks down on humans, considering them "pathetic", and has no mercy for others, even to those who serve him, as shown in his Tales of Souls path where he considers killing his loyal servant Tira. Nightmare's Tales of Souls also shows that he doesn't need to eat or drink to survive, since when he reaches the Grand Labyrinth, he does not carry food provisions like the other characters. However after gaining Graf Dumas (implied to be Raphael) he now gains mainpualtion and decides to rule rather than destroy which makes Tira very upset.

Trivia

 * Both Siegfried and Graf Dumans are blond with similar looking bat winged helmets.
 * Nightmare wields his sword with his left hand in contrast with Siegfried wielding his sword with his right hand.