"The Undead Pool (The Hollows, #12)" by Kim Harrison

There is wild magic loose in the Hollows and it's gunning for Rachel. Why? No one knows, but when a Goddess loses her thoughts, they have to go somewhere. Living vampires fighting for their right to choose death or not, master vampires unexpectedly falling into an endless sleep causing chaos, magic spells misfiring with deadly consequences, elves and demons still fighting over a past history which cannot be forgotten. Just another day for Rachel. When you throw in an undeniable attraction to a man who is off limits and could be the love of her life, things could get complicated. In case there's anytime to take a breath lace it all with little voices that come and go; but these voices aren't just visiting, they wanna stay. What's a girl to do? Simple. Do what the only demon day walker can, her job.