Bloodcaster Chronicles

He's an angel. She's a demon. Their love was never meant to be. Cora is a demon, and an assassin who never misses her mark. But she has a deadly secret: her blood can create the most powerful magical elixirs in the world-and she's been hunted for it her whole life. When Cora is sent to kill a Nephilim named Vince, she figures this will be an easy target. Until Vince time travels, appearing in two places at once.
When she tries to get close to him to learn the secret to his strange ability, she falls in love with him. Her loyalties shift, wreaking chaos among demons and Nephilim alike. Vince toes the line between Nephilim and time travelers, trying to balance both worlds. As he struggles to come to terms with his magic, he uncovers a deadly enemy that transcends the laws of time. Cora and Vince must rely on their skills-and the strength of their love-in order to survive.
But when their enemies align, the star-crossed lovers must confront their battles head-on before the world is torn apart. Even if it destroys them both.