Silently, ponderously, they float through the Astral Plane, mammoth isles of rock adrift in an endless sea of silver. Once they were gods. now they’re little more than debris, petrified husks of fading belief and forgotten prayer. Yet for many, their memories linger, their dreams live on – and for some, those dreams are terrifying nightmares of vengeance, conquest and death.
After that, take a look at your wiki. There is some more helpful info there.