But that's a slight deviation from the way that Viserion was portrayed in the books by George R. R. Martin. In
A World Of Ice And Fire, Martin says: "Of all the queer and fabulous denizens of the Shivering Sea, however, the greatest are the ice dragons.
"These colossal beasts, many times larger than the dragons of Valyria, are said to be made of living ice, with eyes of pale blue crystal and vast translucent wings through which the moon and stars can be glimpsed as they wheel across the sky."
"Whereas common dragons breathe flame, ice dragons supposedly breathe cold, a chill so terrible that it can freeze a man solid in half a heartbeat."