I had an interesting theory about the Mad King. As we all know, his last words were “burn them all”. Most people believe this rant is a result of his Targaryen madness, but I think there is something else at play. The reason for this is because we got to see what Bran Stark was capable of after his training with the three-eyed raven. As Bran and Meera Reed flee from the White Walkers, Bran’s mind in the present became connected with Hodor’s in the past. As a result, Hodor had a seizure and kept saying, “Hold the door” until it slurred into “Hodor”. I think something similar happened to the Mad King. Maybe when the White Walkers invade Westeros, Bran’s mind became connected with the Mad King’s mind. As a result, the Mad King would likely say “burn the Wall” until it slurs into “burn them all”, which Jaime Lannister said he kept saying even after he stabbed him. We shall see as the White Walkers eventually invade the realms of men once again.