Originally Posted by
Ethenil
After reading dome posts, I've made a nice theory (at least to me) :P
We have seen in the warlock questline dialogue posted not long ago that the Doomguards were originally Titanic creations purposed to guard the magical ways. Here s where my speculation comes in:
Let's say the Titans find a great Darkness "under" the planets or even the Twisting Nether itself, and then create a race to guard it off. They make them angelic beings, with wings and all, just like angels as we know them, and send them to all worlds (in secret, perhaps, so even the Tribunal of Ages does not know it) to retrieve the souls of those who are pulled to this Darkness before their time. The Titans name this race the Nathrezim.
Just like Sargeras made the Eredar into Man'ari, he makes the pure form of the Nathrezim into Dreadlords, who then join the Burning Legion, forgetting their original purpose. However, those sent to Azeroth are still pure, and are the Spirit Healers we know today. Then, long after, the Lich King, guarded by the Dreadlords, learns their secrets and is able to morph the Vrykul into a different form of corrupted Nathrezim, and calls them Val'kyr.
Or maybe its got nothing to do with this. A man can dream :P