A thought about the Cannibal. Why didn't the Targaryens gather a group of dragons to kill it? They don't seem to be afraid of riding dragons into battle against other dragons even when it is hopeless. If they brought four or five dragons to bear on the Cannibal it would have been no contest. The reason to do it is that the Cannibal feeds on other dragons and has been known to come down on Dragonstones hatcheries to "gorge" on hatchlings. If dragons are precious, why would the Targaryens let this one old wild dragon repeatedly kill multiple young dragons?