The Last Rider - Mist Riders, #6

Nothing lasts forever. Sure, everyone has an opinion, but when the Oracle of Delphi includes you and your dead-beat Dad in a doomsday prophecy, it's time to click off your phone and listen. Although, as Luna finds out, it's pretty much straight downhill from there with slimy necromancers, demon badgers, weaver assassins and cave golems, all a part of the grotesque menagerie taking part in her certain demise. The worst part.
some dude called the Nightbringer is coming, or so she's been warned. He's a dark rider with great powers whose sole imperative is to destroy her. Fun. If Luna can survive that and all the rest and every little thing goes just right, she'll be stuck in another realm forever, hunched on an Eternal throne. In other words, she'll have the job from hell where retirement is death. And her man Winter? He's gone mortal.