“I do not need to frighten you, Renly. I never did, as your death proved. I tried to warn you as a brother would warn another but you didn’t listen.”

The last word is said with more emotion that he’s put into anything he’s said so far. Because Renly never listened, never even cared, never truly understood. Renly forced his brother to kill him and not even that seemed to stop his reckless behavior. Stannis should be afraid, maybe. He is talking to a ghost of the past after all, a spirit. He should maybe feel guilt, remorse- R'hllor knows he feels a pang of it every time he sees a damn peach, even though Renly had left him with no other possible options.

But all he feels is anger because his little brother won’t even stay dead, not even killing seems to get his attention. Even when being murdered he’s happier, nicer, kinder than Stannis will even be. Even when dead Stannis doesn’t seem to be enough for him because he wants more, grander, brighter. Even when R'hllor tosses him into the shadows he still. Won’t. Listen!

“I killed you, brother. I have lived with that knowledge for a long time now.”