She is the boss amongst spiders, since they're her kin. She has a nasty aura capable of poisoning a pure spirit, and she can pull up a spiritual barrier which is why the Tengu can not enter.

She's the one who kidnapps Zashiki Warashi and ate Watanuki's eye. She hates people who do not appreciate what they have and want to sacrifice themselves. After teaching Watanuki a lesson on that and eating his eye, she lets them go. She is an interesting creature since we can't be sure sure if she is good or evil.