"The sword ravages flesh with teeth of metal and flame, leaving only scorched remains."

As a fledgeling vampire Kain found the flame sword deep within the Termogent Forest, during the events of Blood Omen. When swung the blade would burst into flames instantly cauterizing the wounds it dealt and setting its victims alight. The nature of the sword prevented Kain from feeding by burning the remains of his opponents, it was particularly effective against undead enemies. It is unknown what happened to the Flame Sword following the events of Blood Omen.