Marauder Kain by Aya Morningstar

In a world of darkness, she is his only light.

When Kara’s ship gets stranded on a cold rock on the ass-end of the solar system, she knows that her chances of a knight in shining armor rescuing her are slim to none. But when a light in the sky turns out to be none other than a Marauder with shining teal armor and rippling muscles who lands and saves her, she thinks her luck is too good to be true. And it is. He’s Kain, Son of Grius, and he’s from Darkstar. It’s a barren world beyond the orbit of Pluto, and it’s the home base of Marauders who want to obliterate the human race. But before they eradicate humanity, they’re perfectly happy to take human females as slaves.

Kain Son of Grius has betrayed Darkstar and become a peacekeeper. His mission? Go back to Darkstar as an undercover agent. But on the way, a distress beacon from a stranded human ship takes him off course. It takes just one look in that human’s eyes, and his entire life goes off course. He thinks he might be able to save her, but before he can, a fully-armed ship from Darkstar approaches. He’ll have to go on with his undercover mission, and he’ll have to take his potential mate as prisoner.

If he wants her to survive, he’ll have to claim her.