[The sacrifice is only giving him a small moment in the material world and in taking that moment, he owes her the information. Especially since the price she's paying for it isn't just the life of the dead bird, it's giving him a few minutes to have a chance to steal a new face. That is worth something, even if he walks away with empty-clawed.]

[So he is bound by the constraints of the summoning. He took her up on the deal and he must pay the price.]

[His face changes to that of an angry man.]

The dark wooded path has many threats. Beasts and beings that would do you harm. There is a man among you that spoke of these threats and he spoke true.

But the spiders of these woods now have one they fear more than they themselves are feared and this fact should give you pause. A great and ancient evil has found a home in these woods that did not live there before. That is all I'm bound to say.