My theory is based on the assumption that the Heller has written much of the Mentalist Red John arc as a pseudo biblical metaphor.
William Blake was a Christian and his paintings and poems were all symbolic of the struggle between good and evil.
The 666 clue in episode 1 is symbolic of the unholy trinity that is headed by the Anti-Christ (i.e. Red John). 3 dots are the "mark of the Beast" so all who have it are followers of Red John.
In the Bible, the Anti-Christ rises to power on a platform of peace. He's charismatic, articulate and worshiped. Everybody that falls under his spell is deceived and will gladly do his bidding, even unto death. In reality he's the devil incarnate but they only realize it just before they die.
He's mortally wounded in the head at some point, but rises again and is ultimately vanquished by Christ in the final battle.
The ONLY person that truly fits those requirements metaphorically is Stiles.
Everybody thinks he's a kindly old father figure to Jane. Jane even said to him "You'd never hurt a fly".
But Stiles controls and deceives people and in their delusion they would do anything for him. Remember the dinner scene when everybody stood up to prevent his arrest?
At his ascension ceremony in the previous episode he said not to mourn for him, he will come again. So look for a death and resurrection in the next two episodes.
Stiles "loves" Patrick because only Patrick is worthy to take his place.
He wants Patrick to bow before him so he can pass on his kingdom. However, Patrick can't be tempted by that.
As for most of the RJ killings we've seen throughout the series, they were committed by unholy "sons" killing in the image of their "father" trying to please him in order to inherit his earthly kingdom.
