In the home version of Soul Edge, an extra character named "Siegfried!" was added as an unlockable character. "Siegfried!" was an alternate version of the normal Siegfried taken from his no-input ending, where he was consumed by Soul Edge. This early version was very different from the former Nightmare, having crimson-red armor and a more flesh-like design, almost like if he was part of Soul Edge itself. He has no story nor ending, and only used Siegfried's Soul Edge without effects.
- See main session: Nightmare's Weapons
- Siegfried! wields Soul Edge (that has not grown) and in Soul Calibur III it's called Soul Edge (Cocoon).
- Starting from Soul Calibur III, Nightmare is not Siegfried's alter-ego anymore, ending "Siegfried!'s" appearances on the series.
- If "Siegfried!" had remained on the series, Nightmare would have donned the crimson armor and would then be called "The Crimson Knight" rather than the Azure Knight in all the other series.
- Whereas Nightmare's right arm is mutated, Siegfried!'s left arm is mutated. Interestingly, this makes more sense as Nightmare/Siegfried! holds Soul Edge primarily with his left hand.