Pravuil
Bona na Croin
Not that I'm very knowledgeable concerning these books, but I would assume taking control (if at all possible) of a magical creature would be drastically different from assuming control of any other creatures. If magic began to die in the world solely because of dragons becoming basically extinct (aside from Dany's eggs and any other unknown eggs/dragons Martin hasn't mentioned in his book, if they exist), then it can be seen that dragons are immensely powerful beings.