Quote Originally Posted by Renegade Paladin View Post
Then why the hell did the Emperor not kill him at once upon the discovery of Lorgar?
Specifically, because Lorgar grew up having psychic visions of the Emperor's arrival in his dreams - a beautiful golden God-being who would come and unite all humans - and Lorgar was preaching that as the New Faith. A huge religious civil war broke out between those who followed Lorgar and those of the Covenant (aka, the Old Faith), and Kor Phaeron - despite being an fervent believer in the Chaos Gods - followed his son because he saw it as an opportunity to ride on Lorgar's coat tails to a place of influence and authority.
So when the Emperor arrived on Colchis, the Old Faith of the Four Gods had been suppressed out of sight, and all he knew of was Lorgar's unflinching devotion to the Emperor. Kor Phaeron, as far as any could see, was the second most influential priest of what would become the Cult of the Emperor, and he hid his outlawed beliefs for the next 160 years.

Later, when Monarchia was toppled and Lorgar was bereft of hope, was Kor Phaeron's opportunity - now he had influence and authority - and he used it to guide Lorgar back to the Old Faith, of which Kor Phaeron was the pre-eminent expert.