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Kaena007
Since: Dec, 1969
PaulA
Since: Jan, 2010
Bealocwealm
Since: May, 2019
DomaDoma
Since: Jan, 2001

A book where this girl is being called by evil spirits from within the walls of the house. I don't think it's her house. She eventually answers the call of the evil spirits to rescue someone, maybe her grandfather. The evil spirits live in this sprawling underworld and give off kind of a Tim-Burton-meets-Cyriak vibe. They all feed off something like blood or tears or emotions or whatnot, and she meets a werewolf who feeds on something marginally less creepy than the rest and falls in love with him and forgets all about the quest for a few weeks. The werewolf's name is something like Syldra. I think the main antagonist puts a lot of pride in being a formal gentleman. The version I read was a shortish mass-market paperback with a yellowish cover.
Also, there's a really vivid spoiler concerning the werewolf thing, but I'll hold off until people respond to what I've got.
Edited by DomaDoma