User blog comment:DeirdreKent101/Which Daedra Lord...../@comment-4873968-20130104210605

The sun, according to Dawnguard, is actually a representation of the link between the divines and Nirn. I think that the entire intent of Molag Bal creating vampires was an attempt to remove the connection between Aetherius and Mundus, as he couldn't block the sun directly for some reason. He knew that a mortal that is hurt by the sun would hate it.

Molag Bal truly intends to invade Nirn.