Gena Showalter 
Darkest Whisper [EPUB ebook] 

He destroys all those he loves with a single word… Sabin is bound to the most malicious of spirits. The joining makes him immortal – and ensures that Sabin will face eternity alone. Even the strongest woman cannot resist the constant pinpricks of Doubt. Sabin is searching for Pandora’s box, the source of his demon, when he rescues a beautiful woman who soon reveals her darker side.Gwen has spent her life trying to ignore her powers. Now they are uncontrollable and Gwen is dangerous. Sabin must teach her to contain her terrifying rage. And his reward will be Gwen – the one woman who can overcome his demon’s evil whispers.