Tristan's Wolf (The Wolves of Mt. Alexis #4)
Kelex

Little does Tristan know that he’ll find his mate on that mountain.
Paul has fought the raw power he felt coursing through his veins, fearful he couldn’t control the beast within. But when his mate is hurt, there’s nothing left to hold the tattered edges together.
Once the enemy is defeated, Paul assumes he’s free to have his mate but Paul learns he has another battle to face. To keep his lover, he might have to take on more than he bargained for.
And face the beings who stood by and watched his parents die.