Clay Unto Worlds
The elves as they are known today are a far sight different from their origins- something which can, in the end, be traced back to a split that occurred many thousands of years ago.
In the beginning, when the elves awoke they found themselves deep in the wilderness, among the children of Kovolok. Here they struggled to survive, attempting to master the arts of the wild and building something of a civilization. But they did not struggle unobserved; both Ratagost and Morena had taken notice, and each offered aid in their own way. Ratagost picked elves at random, and taught them many secrets; during the night these elves faded from the world and were sheltered in the Feywild. The Queen of Spiders made herself known to others, offering tutelage in the secrets of magic; those who chose to follow her found shelter in the Shadowlands during the day. Those who chose neither path remained in the world, learning their own ways to survive.
Time passed, and soon it became clear that each branch of the elves were touched in their own way. Those who spent time in the other realms were altered, physically, and found themselves able to call upon the forces associated with those realms. Meanwhile the elves of the world mastered the wilderness around them, relying upon the skills they had learned out of necessity.
The greatest schism between the three came about when those elves of Ratagost, calling themselves the Eladrin, realized that even in comparison to the long lives of the elves, they were effectively ageless. This created an inevitable tension with the followers of the Queen of Spiders, calling themselves the Drow, who saw this immortality as an offense against the natural order.