In one of my quests, I identified Joriah Winter as a roaming Jaysek Priest.
He is undercover, using an illusion to disguise his affiliation to Jaysek.

• Given the support Jaysek is giving him, it takes a Spellcraft roll of DC35+ to determine the illusion even exists.
  
• A spot at DC40+ can be used instead to notice that there is something odd about him.
  
• Seekers of Jaysek will recognise him as one of their own immediately.
  
• Members of Jaysek church can make a lore check (DC25 for SM, DC35 for Masters, lower ranks are too junior to know him.) to see if they know of him.
  

Joriah will never EVER acknowledge that he is a Jaysek priest, even if directly confronted with it. He will guard his identity as best he can. He is though an extremely gifted pick-pocket and will tend to slip pieces of information to people he has determined are on his side.
Should any player compromise his position (deliberately, by basically announcing it to the world at large) the Church of Jaysek will see this as an overtly unfriendly act, and will look unfavourably on the player from that point on.