A Cosmology of Monsters

As is fairly common for me when reading a horror novel, I enjoyed the reading of the majority of this book and then it kinda fell apart for me at the end. Something about the big, final “battle” or whatever of the horror plot always just leaves me feeling....like I missed something? Or something more needs to happen?

Anyway, mostly quite enjoyable book about a boy who discovers his family has been generationally haunted by a particular monster.