I need to give the hero some magical way of deal with the nightmare creatures. Something like -- oh, a bridle of moonlight. Or something equally magical.
I have a way for him to learn how it's done. (It involves a ghost.) What I don't have is a way for him to do it.
grouse, grouse, grumble
And of course it's not a world where he can just go buy it. And his companions are two knights and a scholar, not a wizard in their number. Not to mention that he's not in a position to find one to help.
Going to need some work there.