Fastlander Phoenix by T. S. Joyce

Wreck Itall is haunted by his past, and by his destiny in the mountains he has decided to call home. His mentor has been waiting to see which side he will choose—good, or evil—but Wreck himself doesn’t know that answer quite yet. He is the newest member of the Fastlander Crew, but they are very different from him. It is safest for everyone if he remains an outsider. If the Crew knew how dangerous he really is, they wouldn’t have ever let him pledge.
No one can stop him.
No one can tame the monster inside of him.
No one can break down his carefully-constructed walls…until he meets Timber.
The quirky beauty has a dark destiny of her own, and awakens something inside of him that can never be released onto the world. Wreck knows it is safer to stay away from her because she is human, and has no idea what destruction is coming for Wreck and his Crew. It’s not fair to put a human in the middle of the war that has been building for so long, but he can’t seem to leave her alone. All he knows is that she brings out a side of him that could be the end of the world, and will absolutely be the end of Wreck. She dredges up the monster.