Dark’s Savior by Olivia Riley

A chance encounter can change everything.

When Aly joined the Grayhart mission to find advanced civilizations within deep space, she didn’t expect to be captured far from home and taken to Xolis–a galactic empire like none ever seen, ruled by the nillium–a powerful race with a serious god complex.
Now outsiders, Aly and her team of explorers are sent to the darkest place within Xolis: Lethe Maws. A mining city on a planet home to outcasts, slaves, and monstrous creatures lurking in the deep dark.

And home to the Dark One, a dangerous exile even the nillium fear, living at the bottom of the mines where all are warned never to go.
When Aly runs into the legendary alien in a very unlikely place, what she finds is no monster but a large, mysterious, nillium male with fierce silver eyes, who makes her heart race.
But though the nillium outcast had reached for her, desiring to touch her, fascinated by her as she was of him, Aly soon learns he’s not looking to be friends or possibly something more.

For what Aly doesn’t know is the Dark One–known by his kind as Ryziel, son of the nillium’s now dead ruler–isn’t looking for love or a mate. He’s looking to get off Lethe Maws for good and return home to his brother, the only family who accepts him for who he is, the only one who matters.
But the human woman brings out a darker part of him that he can’t control–something he never thought possible. As he is determined to escape, he struggles to understand his need for her. A need to protect her. A need to claim her. But determined not to let her get too close lest she be his undoing.

Try as he might to keep her at a distance, Aly will become the one thing Ryziel needs to be free.