Siegfried Schtauffen is the Main Protagonist of the Soul Series.
Siegfried was born on February 6, 1568 in Ober-Getzenberg, Holy Roman Empire (Now Germany) to Frederick and Margaret whom they named after the hero of the same name. Over the course of the next ten to fifteen years, Frederick spent a lot of his time teaching his son swordsmanship.
Embarking on a foreign crusade, Frederick promised Margaret that he would return; unfortunately, without his father's guidance, Siegfried began to socialize with an edgy clan of teenagers, and he soon became the leader of their band of thieves known as "Schwarzwind," meaning "black wind." In a misguided act of national pride, the band devised a plan to attack the knights who ran away from the crusades, as they were bound to carry valuable possessions, and were too cowardly to deserve respect in any case. That night, the "Schwarzwind" ambushed a group of war-weary soldiers, too tired to retaliate. Siegfried even managed to kill the commander himself; but as he held the commander's severed head in triumph, the moonlight shone on its face, and Siegfried screamed as he realized he held the head of his own father. In mere seconds, Siegfried's mind had broken upon which point he ran straight into the forest, becoming more and more insane as he ruminated over his previous acts, until he came to a point at which he psychologically convinced himself that his father's murderer was actually someone other than himself. Hearing rumors of the invincible Soul Edge, Siegfried came to believe his father's killer could only be killed with said weapon.
During the following three years he gathered together a group of followers: the golem Astaroth, the lizard man Aeon Calcos, and the alchemist Ivy. Each of them aided him in Soul Edge's quest to devour souls for a rejuvenation ceremony to be performed in his chosen stronghold, Ostrheinsburg Castle. But as the ceremony was about to take place, the clan was quickly laid to waste. Both Aeon Calcos and Astaroth were defeated; and Ivy left the clan after learning the shocking truth of her horrifying past from the Fu-Ma ninja, Taki. Two young warriors confronted Nightmare after slaying many golems: Kilik, owner of both the sacred staff Kali-Yuga and sacred mirror Dvapara-Yuga; and Xianghua, owner of Krita-Yuga, which revealed herself as Soul Calibur.
The battle between the swordsmen took place in a vortex of hellfire and evil energy summoned by Soul Edge. After a raging battle, the evil sword shattered, and Nightmare and Soul Edge fell into the collapsing void. With Soul Edge severely weakened, Siegfried regained some of his humanity. Along with lucidity came the horrifying memories of the sins he committed, as well as the fear and anger of those who were slaughtered by him. Moreover, he realized that he had been the one who murdered his father, and that his "resurrection" was only an illusion brought by his mind.
Expelled from the void into an unfamiliar place, Siegfried disappeared into the night-the evil sword still in his grip. But Soul Edge was weaker now, and splinters of itself were left in Siegfried's footsteps. Siegfried meditated on all he had done and eventually learned to accept responsibility for his sin. He planned to return to his mother, who had no knowledge of anything that occurred during or after that night three years ago; but just as he was about to knock on the door, he could hear his mother praying, and concluded that if he was to be successful in his new resolve, he must distance himself from society so that he never kills again. He could not see his mother until he was fully redeemed; but he knew he was not yet atoned for, for every time he awoke from a night's rest, he found his new zweihänder Requiem covered in blood, and he was surrounded by the corpses of victims he had presumably murdered in his sleep.
Main Article: Nightmare
Siegfried was aware that although he had regained his sanity and learned to accept his past sins from three years ago, he was not yet fully redeemed. He knew that Soul Edge still held power over him, but now it used its strength in his sleep, and no matter how hard he tried not to fall asleep again, he would always eventually give in, and the darkness would continue to operate at night in his subconscious. He tried to forsake civilization as far as he could go, so that no person could be corrupted by the dark energy of the Soul Edge, but to no avail.
Four years passed, and he had eventually assumed the azure armor for a second time, becoming Nightmare all over again, desperately pursuing fragments of the Soul Edge that he might fully restore it. As Nightmare plundered powerful souls and recovered shattered fragments of the sword, the cracks in Soul Edge healed one by one. His goal of reviving the evil sword edged toward completion. After some time, the Azure Knight returned to his old stronghold, Ostrheinsburg, as its bloodied land was a fitting stage for the restoration of the evil sword's true power.
In the ruins of the chapel, a lone fencer, Raphael Sorel appeared in search of Soul Edge. The two of them faced off, but at the end of the fierce battle, Nightmare stood victorious. As he stepped forward to finish Raphael off, he muttered something incoherently.
Deep within Nightmare's eyes a faint light dwelled. It was the will of Siegfried. As he struggled to free his mind from the influence of evil, the spirit of the sword sneered at him. The two held a formless fight, as Siegfried struggled to take his body back while Inferno mocked him and his father. (Sometime during this, Raphael made a desperate last strike and damaged Soul Edge, a contributing factor to Siegfried's final escape.)
The battle raging deep within his mind caused the Azure Knight to stand motionless. Beside him, the wounded body of Raphael trembled. Only Raphael's great will enabled his gravely injured body to move. Drawing on his last strength, Raphael unleashed a desperate final blow upon his enemy. The strike pierced the center of Soul Edge.
Nightmare let out an inhuman cry. Inside him, the crazed, wounded mind of the evil sword clawed at his consciousness. Siegfried stood with an iron will against the raging storm, and finally restored control. He who had been lost to the cursed sword for so long had reclaimed his body as his own. In response to the rapidly weakening evil, light poured out like the coming of the dawn...
When it was all over, Siegfried thought back in a daze over what he had done. As he looked around, he sighted a sword that appeared along with the light. As if guided by something, he took the sword in his hand and drove it into the evil eye that was the core of Soul Edge. That sword was the holy sword Soul Calibur, which had been trapped by the power of the evil sword.
The blow, however, was not enough to destroy the evil sword. The evil energy of Soul Edge had quieted, but the holy sword, still piercing cursed sword, had gone silent, as if it too, had lost its power.
"This isn't enough..." Forcing his exhausted mind into motion, as he began to think. He threw off his detestable armor and smashed it into pieces. Then, picking up both swords, he left that cursed land. "I will seal away Soul Edge for all eternity and atone for my sins. This I swear!" His bloody fate would not release him so easily, however. From time to time, the feeling of that grotesque arm rose from the depths of his memory. The residue of the nightmare tormented him. Those seeking revenge on Nightmare would occasionally appear in his path. Each time he was forced to fight them, his mind was wracked with guilt. Moreover, Siegfried did not realize that another dark omen was on the horizon. Indeed, there was no way for him to know that the azure knight would soon be revived and a man who wanted to end an ever-lasting curse wanted the two swords in order to do it.
Eventually, Siegfried and the resurrected Azure Knight would meet again at Lost Cathedral. Zasalamel used his dark arts to break Soul Embrace and both the Spirit Sword and the Cursed Sword were freed. Both Siegfried and Nightmare took their respective swords and clashed one more time, causing an explosion that destroyed the entire cathedral and nearly destroyed them both...