I am sure one of the Istvaan's were purged again, think it was Istvaan V. It was by a Chapter along the lines of "Desert Tigers" although this is taken from Lexicanum, and the actual source I believe is from older fluff. I wouldn't be suprised if they became some sort of shrine, pilgrims coming back and forth and all however.
Nyctophobia- Fear of the Dark Angel.
"No one ever spoke about of those two absent brothers. Their separate tragedies had seemed like aberrations. Had they, in fact, been warnings that no one had heeded?"
'Killing a man is like fucking, boy, only instead of giving life you take it. You experience the ecstasy of penetration as your warhead enters the enemy's belly and the shaft follows. You see the whites of his eyes roll inside the sockets of his helmet. You feel his knees give way beneath him and the weight of his faltering flesh draw down the point of your spear. Are you picturing this?'
'Is your dick hard yet?'
''What? You've got your spear in a man's guts and your dog isn't stiff? What are you, a woman?'