The mighty dragons are the most decisive resource in Game of Thrones. Aegon the Conqueror flew a few winged nightmares from one end of Westeros to the other until all were united beneath his banner. When his distant descendant acquired the last three dragons, the world seemed to shift on its axis. Though dragons and their riders dominated for generations, they aren't the only winged reptile in the Known World. Wyverns are dragons without the cultural cache.