To be a priest in the Taiidan religion they are usually those who cannot go to war, maybe due to genetic mutations that make them not very good in combat or those who wish to follow their god. When you are accepted into the Priesthood you are to go away to a secluded place and build a mask. This mask embodies their face and they must become the mask leaving behind their past lives. The priesthood isn't allowed to show their face to anyone not even their wives. They are always given an implant that emits a sonic wave that activates when they stretch out thier hands, this doesn't affect Taiidans but it does affect everyone else. Many believe the Taiidan Priest to be gods as they can cause entire armies to fall to the ground asleep, as the Sonic waves damages the eardrum and knocks them out. This has been used as a symbol of fear.
Those who became priest were once normal people but they chose a life of solitude. Most of the history of the Pro'juuk is unknown as they kept it a secret what is known is that they protect their god a living Progenitor named Nigrash.