Siegfried, the former holder of Soul Calibur, used this zweihänder during his mercenary days when he was searching for Soul Edge. It is probably this very sword that Siegfried used to spill the blood of his own father. It was once broken, but was later restored by the cursed power of Soul Edge.
Faust is one of Siegfried's weapons in Soulcalibur IV. It can be bought in Character Creation for 8,000 Gold after completing Story Mode with Siegfried.