Soul Edge α is the form Soul Edge took when first wielded by Siegfried in Soulcalibur Legends. Before its evil took control of Siegfried and changed him into Nightmare, he used it as his own weapon for a short period of time. In this form, it isn't terribly strong; as it was just recently separated from half of its full mass. It is suggested by a very scarce amount of players that think that this version is the version slowly growing into Soul Edge.
Aside from being Siegfried's primary weapon in Soulcalibur Legends, this form has made two different cameos. In Soulcalibur II, it was Nightmare's second player outfit's default weapon, and in Soulcalibur III, it appears as one of Nightmare's unlockable weapons.