Emergence (Gideon Wolf, #1)

Maybe the hero humanity needs is actually a monster.
At first, Dr. Gideon Wolf thinks the guy standing in front of him is insane.

Ten million bucks for what amounts to a glorified treasure hunt. Ten million dollars, this man offers him, to find a mythical amulet based on, apparently, some maps he printed off the internet and his outsize faith in make-believe.
Turns out the unwelcome interlocutor isn’t just some garden-variety kook. He’s Vicente Carrillo, the world’s most feared drug lord, and Gideon learns fast that the deal is nonnegotiable.

Held captive by Carrillo’s thugs in the Mexican jungle, Gideon escapes before the expedition . . . only to stumble into an ancient, hidden temple that contains the medallion itself.
The instant he touches the amulet, he knows why Carrillo wants it. It exudes a power that makes him feel invincible.

But there’s a downside. The medallion has disfigured him horribly. What was once the respected archaeologist Dr. Gideon Wolf is now a bloodthirsty monstrosity: part wolf, part dog, part man.

“El Chupacabra,” a cartel gunman gasps as Gideon bashes his skull in an escape.
Gideon’s amulet is one of seven, hidden by the ancients millennia ago and bestowing great responsibility on whoever finds, and dons, the powerful artifacts.

To fulfill his destiny as El Chupacabra, the Guardian of the Innocent, he must first learn to control his all-too-real animal instincts while protecting the amulet from Carrillo, who’s launched a private army straight at Gideon to steal it back.