I seem to have stumbled upon another connection between "Light" and damaging spells:
The http://www.uesp.net/wiki/Oblivion:Aurorans use a damaging spell called "Light that Burns" that both does Shock damage but also casts an Illusory Light spell. (Their protective shock shell is called "Light that Protects") Umaril himself uses "Mortal Light" which doesn't cast the Light effect but which does a lot of damage, and in the Song of Pelinal was said to be "bathed in Meridian Light".
It seems logical to me that perhaps in lore Aurorans and other servants of Meridia, who was once Aedric, use damaging Light spells, but due to the restrictions of the game engine (namely the fact Light spells in Oblivion don't do damage but simply light up a room), a Shock effect was added to account for the damage.
So that's another possible vague connection between the Aedra or at least the et'Ada in general and the concept of "Light Damage". *shrugs*
It's not much but it's mildly interesting to me, especially for the RP'ing possibilities.
I can't help but think that the OP hasn't seen Lord of the Rings, but I'm too lazy to search youtube for the fragment where Gandalf uses the Streams of Light against the Nazgul. Now I do have some hentai on hand here that also features streams of light ....
I've seen the entire trilogy numerous times and read the book twice. I know about Gandalf and his abilities - but he was no Battlemage or even Wizard. He was a being comparable to an Archangel in the guise of an old bearded man, so that ability was less a spell and more a Divine Ability. Although, as I said, the abilities used by Aurorans or certain mortal champions such as the Paladins occasionally mentioned in Lore may be less spells and more inherent Abilities as well.