The fifth book in the Rachel Morgan series is probably the best. Beware of spoilers, they be ahead.
Rachel is a 20-something Earth witch who has been working ley line magic and dabbling in demon spells. Granted the demon spells were to save her friends, but demon spells leave smut and Rachel's aura is coated it in. Word has also gotten around that she is a demon practitioner. Weres are being murdered in this book and it's discovered that The Focus can actually turn people into werewolves. David, her alpha, has been sleeping with quite a few ladies and they've all been turned.
Trying to figure out how to deal with the Focus, Al the demon, Newt the crazy demon, Ivy's desperate need to have Rachel, blood and body, plus Trent's wedding almost proves too much for Rachel. With a lot of screw ups, we have to remember she is only in her 20s, she does manage to bring some peace to the fighting were packs and still have some good birthday sex with her boyfriend, vampire Kiston. (Wow...that scene.)
Things turn very very ugly and Harrison hints at the unthinkable....then does it. Main characters are actually killed off in book 5! We, as readers, had 4 books to really get to know these people and wow....good on you, Harrison
Already downloaded book 6 to read.