» Mon May 07, 2012 10:04 pm
"As he entered every aspect of Anuiel, Lorkhan would plant an idea that was almost wholly based on limitation. He outlined a plan to create a soul for the Aurbis, a place where the aspects of aspects might even be allowed to self-reflect. He gained many followers; even Auriel, when told he would become the king of the new world, agreed to help Lorkhan. So they created the Mundus, where their own aspects might live, and became the et'Ada.
But this was a trick. As Lorkhan knew, this world contained more limitations than not and was therefore hardly a thing of Anu at all. Mundus was the House of Sithis. As their aspects began to die off, many of the et'Ada vanished completely. Some escaped, like Magnus, and that is why there are no limitations to magic. Others, like Y'ffre, transformed themselves into the Ehlnofey, the Earthbones, so that the whole world might not die. Some had to marry and make children just to last. Each generation was weaker than the last, and soon there were Aldmer. "
Source: The Monomyth
If Alduin is a 'child' of Akatosh, he would be Ehlnofey, I think.