Mythic has posted lore about the Elves in Warhammer Online, providing an overview of their origins.
Even the Elves themselves are unsure of their exact origin, which was lost in the dawn of time. What is known, however, is that they come from the beautiful Isle of Ulthuan where they lived and prospered for centuries in peace and harmony, learning the arts of the Old Ones. Blessed with grace, beauty, strength, and intelligence, they lived for thousands of years in a state of peace that many thought would never end.
When the Old Ones’ Warp Gates collapsed, however, the forces of Chaos arrived. Trapped on their island, the Elves fought bravely against the hordes of daemons that came from beyond the stars, but they seemed unstoppable. Many of the Elves, capable of deep and intense emotions, began to study the way of the warrior, and were in charge of organizing the island’s defenses against the assault. Among these was the greatest and most tragic hero the Elves have ever known: Aenarion, who would later become the first Phoenix King of the Elves.
Read more here.