Maelstrom Chronicles Series by Jody Wallace

He's no angel... Gregori's last mission is to save Earth from the demons threatening to take control. He doesn't care if he survives as long as he averts the impending apocalypse-until he meets Adelita, a human refugee, whose spirit and determination give him a renewed reason to fight. And live. He's falling for her, despite the fact he's told her nothing but lies and there can't possibly be a future for them... moreHe's no angel... Gregori's last mission is to save Earth from the demons threatening to take control. He doesn't care if he survives as long as he averts the impending apocalypse-until he meets Adelita, a human refugee, whose spirit and determination give him a renewed reason to fight. And live. He's falling for her, despite the fact he's told her nothing but lies and there can't possibly be a future for them. Adelita can hardly believe the archangel Gregori, sent to save mankind, has lost his faith and his edge. After he saves her from a demon attack, she vows to help him recover both by any means necessary. But can she keep her own faith when she learns the truth about who and what Gregori really is? less

He was branded a traitor. And he may be humankind's salvation...Captain Nikolas EstherVorn is a traitor. Or so it was decreed after Niko disobeyed protocol while trying to save Earth from other-dimensional creatures. Stuck in a prison cell, the last thing he needs is to be in close proximity to sexy-as-sin Dr. Sarah CallenJoseph. Not with him damn near ready to break out just to get to her.Niko's desire isn't quite his own...and Sarah can prove it... moreHe was branded a traitor. And he may be humankind's salvation...Captain Nikolas EstherVorn is a traitor. Or so it was decreed after Niko disobeyed protocol while trying to save Earth from other-dimensional creatures. Stuck in a prison cell, the last thing he needs is to be in close proximity to sexy-as-sin Dr. Sarah CallenJoseph. Not with him damn near ready to break out just to get to her.Niko's desire isn't quite his own...and Sarah can prove it. He-along with the other soldiers on the disastrous mission-were drugged with some kind of toxin. Niko has no clue how the drug got into his body or why, but Sarah suspects there's a link between the toxin and the fertility crisis of Shipborn humans.To investigate is forbidden. But as lust becomes something deeper, binding them together in a way neither expected, Niko and Sarah must battle time-and their superiors-to uncover the secret that could save humanity...or destroy it. less