Elven Perspective

The earliest known tales of the Elves have had far fewer generations through which to pass and become distorted in the retelling, and thus are generally regarded as more reliable by bards of the realm.
At the same time, since the human species is far greater in number, the human perspective remains the dominant history of the realm.
There come through the Elven people many songs from the time before the Peopling, and numerous songs which appear to have been written since.
The earliest known piece to have been written since the time of the Peopling (or perhaps during it) is the first of the Lays of the Beyonder.
Zephyr Elflord, the Beyonder, claims to descend from another, more powerful, Elven deity, whose sway does not reach the Hinterlands; neither does he dwell in the Summer Country. The Beyonder is all that remains of his court in this realm, and has become the acclaimed Lord of the Fair Folk, followed by many of the non-human peoples of the realm. These claims cannot be verified, of course, but no reliable reason to doubt their veracity has ever been raised.
Early Elven tales make clear, however, that the Elves do not hail from the Hinterlands, having arrived some time after Arawn Deathlord had begun his war against the Ogre Princes. They arrived with the Beyonder, as his court of retainers, including Grey Elves, High Elves and Wood Elves (as well as one known Avariel) and the followers of the Beyonder accuse Arawn Deathlord of having stolen the powerful artefact by which they had arrived, though if Arawn indeed possesses this, he has not made any use of it, having secreted it away somewhere in the deeper bowels of the world.
It was later, but in similar fashion, that the Drow arrived, and may have been in pursuit of the Beyonder and his people, for their arrival was a violent one, their steel spider creeping across the skies for days, raining fire and death down upon the land until the mighty dragon queen, Anu fixed her baleful eye upon it and tore it from the heavens, at which point the Drow abandoned their lofty perch and came down with their slaves to further people the Hinterlands.
Regardless, both the surface Elves and the Drow have established themselves in the Hinterlands, one side in support of the House of Dawn, and with strong ties to it, while the other side serves Arawn Deathlord, and worships his cruel daughter most devoutly.
Most non-human non-Elves in the Hinterlands arrived with the Drow, as slaves, and have been struggling for their freedom ever since. The Drow consider all of these to be expendable, and indeed worthless, being little more than wayward property, while Arawn Deathlord sees many of them as potentially useful.

Elven Perspective

Hinterlands ByakkoChan