Warlord’s Mercy by Cynthia Sax

Other Chameles view him as the enemy.
She sees the warrior hero he never believed he could be.

Tolui is a Warlord in search of a planet to rule. He has been leading his fellow clones in a stealth battle, fighting for both control of the Chamele sector and the right to exist. The brave warriors he commands warrant respect and they deserve the best.
That best isn’t the barren, dangerous terrain on Chamele 4. When Tolui crashes on that planet’s surface, he’s determined to leave it as soon as possible. The tiny human female rescuing him might be as beautiful and as wild as the land she inhabits, but her flowing words, trusting gaze, and enthralling submission won’t stop him from rejoining the war.
After many solar cycles of living alone, Lea is overjoyed when a tall, scarred, muscular warrior falls from the sky. Her savage stranger is strong and severe, and he makes her feel safe, an emotion she hasn’t experienced in a long, long time.
He also insists they must part. Before they do, she’ll show him the splendor of her home, and she’ll enjoy his big form, collecting passionate moments she can revisit when she’s solitary once more.
Every additional moment Lea and Tolui spend together increases the chance they’ll both die. Lea is being chased by female-hating fiends. Tolui is being hunted by the best bounty hunters in the universe. War will soon arrive on their threshold, and the blood spilled might be their own.

Note: Warlord’s Mercy is based on a much shorter story sharing the same title.