Eternal Rider

"They are here. They ride. The Four Horsemen of the Apocalypse. His name is Ares, and the fate of mankind rests on his powerful shoulders. If he falls to the forces of evil, the world falls too. As one of the Four Horsemen of the Apocalypse, he is far stronger than any mortal, but even he cannot fight his destiny forever. Not when his own brother plots against him. Yet there is one last hope. Gifted in a way other humans can't-or won't-understand, Cara Thornhart is the key to both this Horseman's safety and his doom. But involving Cara will prove treacherous, even beyond the maddening, dangerous desire that seizes them the moment they meet. For staving off eternal darkness could have a staggering cost: Cara's life."