Possessed By the Alien Warlord by Krista Luna

Duty demands I claim my fated mate. Yet I will never love her.

KIRA: As the fleet’s best engineer, I work endlessly to keep everyone alive with little more than spit and a prayer. Then an even more crucial job beckons. Survival demands we crack the enemy’s jamming tech, and I’m just the person to do it.
But the new job is on-planet, and the only way to get there is to marry a Varool.
The biggest, grumpiest alien of the big-and-grumpy bunch claims me. I swear Grol’s made of living stone, but his touch is pure fire, freeing my truest desires. I’m falling fast, but Grol’s emotions are impenetrable. With so much heat between us, his indifference could burn my heart to ash.

GROL: Duke, Head of War, Warlord—I go by many titles, none of them soft. I am the sharp tip of the sword aimed straight at the heart of my enemy.
Then she says my name. Grol, simply Grol. This small human is my fated mate.
I claim her to assuage the mating frenzy, almost losing myself in pleasure. Duty demands that I protect her so she can discover a way to defeat our foe. Yet the longer we are together, the more her intelligence and lightness of spirit affect me.
Enemies attack from all sides, requiring complete focus for the fight. For the first time in my life, my purpose is divided. How can such tiny hands have such a strong grip on my two hearts?