The Vortex of Ulthuan, called the Great Vortex, is the vast, roaring maelstrom of magical energy that spins at the heart of the island continent of Ulthuan, home of the high elves — and the single greatest work of magic ever wrought in the world. To the eye it is a titanic whirlpool of sea and storm; in truth it is a drain, ceaselessly pulling the Winds of Magic out of the world and away from the grasp of Chaos.
The Vortex was created in the world's darkest hour. As daemons overran the young world through the ruined polar gates, the high elf mage Caledor Dragontamer and a circle of the greatest sorcerers raised the maelstrom to siphon away the raw magic on which the daemons fed, banishing the horde and saving all living things. The cost was terrible: Caledor and his circle were caught forever in the vortex they made, and they sustain it still, an eternal sacrifice frozen at the moment of their triumph.
Upon this working the whole world depends. So long as the Vortex turns, the tide of Chaos is held at bay and magic is drawn from the world faster than it can pool into corruption. The high elf mages tend it unceasingly, and their enemies — the dark elves above all — have schemed for millennia to unmake it, knowing that to shatter the Vortex would be to drown the world in unchecked magic and open every door to the Realm of Chaos at once.