Wild Sign by Patricia Briggs

Where our favorite werewolves owned some property for the last 200 years.  Some people were squatting on it.  The FBI approached the Cornick family because a resident’s daughter reported it as suddenly abandoned.  The Marrock’s mate, Leah, owns the property.  Something horrible happened to her back then and she was rescued, changed, and mated without her consent.  When Charles, Anna and Tag, an old berserker werewolf, go out to check on the place, something traps Anna, mentally, back into her own worst experience.  Charles pulls her out and when they go to a storage facility owned by one of the residents, they find magic grimoires.  She is a white witch, and notes in her storage leads them to her father in a rest-home.  Only it’s no ordinary place.  It’s a place for black witches and they’re draining the man, an ancient enemy of the werewolves, of his magical energy.  They meet in a garden, which itself exerts a magical influence.  Leah has been summoned by the malign influence and travels in wolf form from Montana to the site.  Bran, the Marrok, is flying in by helicopter with a fey sword to try to kill the entity.  Leah had a surviving son from before and he has become a walker for the entity.  He confuses Anna with magic and kidnaps her.  Charles and Tag discover this an hour later and follow to Wild Sign.  Leah gets there first and before her son can do anything else to Anna, Leah grabs her and tries to pull her from the cave system.  The son confronts them before they can escape, and Anna shoots him in the eye and chest.  They leave the cave and run into Charles and Tag.  But the entity is not dome with them yet and a battle ensues with the entity having taken on aspects of Cthulhu, tentacles included.  Bran appears with the sword, but Tag is so close to dying, he tosses the sword to Charles who delivers a disabling blow.  Leah reenters the cave and finds her son is not dead and regenerating.  She kills him again and returns to the entity with her son’s heart, which she buries in a tentacle and then pierces both with the sword.  That seems to be the mortal blow.  Coyote appears and cheers them on from the sidelines.  He tells them that all of the women, currently pregnant with potential walkers of the entity have miscarried.  Bran takes Leah back to Montana.  When the others are out of sight, Coyote saunters over to one of the tentacles and slices it open.  Inside, the entity is in the form of a small white slug.  Coyote eats it.  Tastes like squid.  Later, coyote visits the rest home and walks into the garden.  He tells it they need to talk.