Decimate by Nova Noble

Neanderthals return to Earth, this time as modified Neander Beasts, ready to take back the planet.

Aria lives a lonely life, sneaking out of the palace on Earth to have just a few moments of freedom without her father, the Anyma sectar, breathing down her neck. It’s on one of these secret trips that she runs into a man who doesn’t fit in with the humans. More importantly, he has a way of making her angry. Very angry.
As the leader of the Neander Beast crew sent to Earth to build their new headquarters, Jezper has a secret mission of his own: find as many females to mate with as he can. Even though it’s strictly forbidden in the strained peace treaty with the Anyma.
If only Aria hadn’t caught his attention. And if only she’d told him who she really was. Maybe then the two alien species wouldn’t be on the verge of war.