At the time, he added, "They're a power man should never have trifled with, one that brought Valyria its doom. And if we don't mind our own histories, it will do the same to us." Ironically, Rhaenyra is trying to heed Viserys' words when Luke is killed by Vhagar, which, if her vengeful look at the end of the episode is anything to go by, will actually trigger her to follow down Daemon's warpath that ultimately leads to the doom of the dragons AND the Targaryens.