Nightmare is the main antagonist of the Soul Calibur series. Nightmare is the dark side of Siegfried. After Siegfried obtained Soul Edge, he was consumed by the dark power of the evil blade. This caused his armor to be possessed by the soul of Soul Edge, known as Nightmare. Nightmare then grabbed Soul Edge and left Siegfried to die. Somehow, Siegfried managed to survive, and had a revelation and decided to seek redemption for his previous wrong doings. Now Siegfried is always on the move to find Nightmare, to get his revenge, and to redeem himself.
Nightmare has many nicknames throughout Tales of Souls mode, but the main one is the "azure knight." Obviously, because his armor is blue.
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