According to some sources, Lolth was formerly Araushnee, the elven goddess of destiny.
Then she became corrupt and turned against the Seldarine.
Personally, I like the idea that she was formerly the goddess of destiny as I see a evolution (devolution?) from a goddess who handled intertwined threads of destiny into the web-spinner she is today.
I've been trying to come up with an idea as to WHY she started down the path she did; but I haven't come up with an idea that completely clicks for me. So I'm asking for suggestions. I don't particularly care if your ideas are cannon or not.
Some germs of ideas I've had were:
-While looking into the future, she saw a threat of some sort and felt that her actions would make the elves strong enough to resist/survive that threat
-A fiend in the form of a spider got into here web of destiny-strands and began corrupting her (like the serpent did in Eden). This fiend was later consumed/synthesized by Lolth
I've got a few other odds and ends, but they aren't very good. So please throw out some ideas. I never like it when someone just "turns evil" for some petty reason. I prefer tales where the path to ultimate corruption begins with a few bad steps that the person rationalizes as needed or justified; and at present, I don't have that starting point for Lolth
Here are some more ideas:
http://community.wizards.com/go/thread/view/75882/19781666/Why_Did_Araus...