Kistrel Sub-Quest: An Overly Clever Arachnid[]
You’ll run across Kistrel in the caves beneath Duskwood and Ember. You can kill her if you wish, if the PC is a Drow, if Elanee is in your party, or if you’re a druid or ranger, you can also attempt to communicate with it. Elanee (or you if you're a ranger/druid) will deduce that the beast is hungry, and that you may be able to feed it if you find some insects for it.
If you head up into Duskwood and find the cave with two gnomes outside, you’ll find the insects inside. (We’ll talk more about that incident in the On Duskwood Ridge sub-quest below.) If you return to the spider, you’ll be able to feed it the bag of insects (we had to leave the area completely and come back for this option to appear.) It’ll ask to come along with you. Accept for a large XP bonus. You’ll see the spider again when you get your stronghold. -stolen from http://www.gamespot.com/features/6161016/p-27.html