Sakim, a word derived from the first language that meant greed. And it was given as a name to one of the first sinners, the first vessels of the seven deadly sins.
Carried by this name was a sin. And carried by this sin was an incomparable power that was feared even by the primordial beings. It was so powerful that it needed the army of God themselves to come down from the heavens just to seal this sin and the others so that they could never bare their fang again.
As the seven deadly sins disappeared, so as the names lost their meaning. No one then was ever worthy to carry these names after that incident since these names were only given to the vessels of seven deadly sins.
And those who tried to use these names as their own were either cursed or had died mysteriously.