Nightmare next? What always confused me was Nightmare was in SCII, but not Siegfried, so it wasn't till later I found out who Nightmare really is. Confusing story is confusing.
Well Siegfried was in Soul Calibur, but only as an unlockable character because technically he was Nightmare up until the end of 2. Then in 3, Soul Edge took on a form of Nightmare without an actual body. Then in 5, Nightmare was once again a human, only this time a human was in control and was simply an evil guy. Yeah I guess it is kind of confusing.