The Holy Artifact is a special item unique to those who ascend to the Holy Rank.
Each Holy Artifact is one of a kind, a reflection of the caster's soul.
The forging process is extremely mysterious, especially the final step, which is said to never have been the same for anyone.
Moreover, many times, experts of the Holy Rank complete the final step of forging their Holy Artifact through a sudden moment of enlightenment.
This enlightenment usually occurs during their ascension to the Holy Rank.
Therefore, those about to ascend to the Holy Rank or those who ascended but failed to forge their own Holy Artifact often carry a Holy Artifact Embryo, so that when the time is right, they can smoothly complete the last step and forge their own Holy Artifact.
Lette's first Holy Artifact, Sin Light, was not well prepared with a Holy Artifact Embryo; it was a standard Holy Knight Longsword he always used to practice swordsmanship.