The World Engine was created by the gods, with task of raising the continents oft he new world from the sea floor.
After time immemorial it was put to rest, only awake once more during the War of the Gods to be used as a weapon.
Since that time it has slumbered, waiting for its final calling. To awake once more and remake the world, at the expense of everything currently on it.
The world engine is a nearly indestructible Earth Elemental with barely any sentience or intelligence. Designed to be controlled mentally by the gods. It is beyond huge. And repersents one of the most dangerous things in the setting besides the gods themselves.