The Soul Calibur was created in order to destroy the evil blade Soul Edge, a weapon originally forged to be an ordinary blade. However, after years of bloodshed, the sword evolved into a powerful instrument of evil, tainting all those who grasped its power with an overwhelming urge to conquer and destroy. Only one man was able to wield the evil sword Soul Edge without becoming tainted by it. This man, Algol, sought to use the sword to bring about peace to the world, and was heralded as the "Hero King."
Unfortunately, the draw of the Soul Edge attracted several men to attempt to steal the blade. The man who succeeded in this was Algol's own son. Possessed by the power of the Soul Edge, Algol's son attacked the Hero King who, with great pain and reluctance, was forced to kill the young man. Algol then knew that the Soul Edge had to be destroyed. By forging the Soul Calibur, and trapping his own soul within the blade, Algol created the one holy blade powerful enough to destroy the Soul Edge.
Over the course of history, the Soul Calibur, passed on through generations by the guardians of the sword, has been used to shatter the Soul Edge and the subsequent blades created from its fragments.