The Game of Thrones universe demonstrates that dragons aren't invincible. They inspire fear, are a deterrent, and strike terror through cities and towns but do not live forever. George R. R. Martin's works describe dragons as serpentine, flying, and fire-breathing creatures that conduce to the prosperity of the Dragonlords of Old Valyria, the might of the Freehold, and more recently, that of the ruling House Targaryen of Westeros.