Captive by Nina K. Westra

Everyone knows that night elves would just as soon kill you as look at you. Novikke has never seen one in person, and she’s inclined to keep it that way.

As a member of the Ardanian army, Novikke has no love for night elves. Her people and theirs have been at odds for centuries thanks to the elves’ penchant for violence and hatred of humans. Every citizen of Ardani knows not to approach their land: a vast forest made of shadows and magic that eats outsiders alive.
So when she’s taken prisoner by Aruna, a night elf with too-perceptive eyes and a frightening, otherworldly visage, she has little hope of surviving.

But when he shows her unexpected compassion, Novikke begins to see her captor in a new light—and starts to question everything she thought she knew about his mysterious people. Beneath his quiet, cold exterior lies a wry wit and a surprising sense of honor—and she’s beginning to think that he feels the same troublesome attraction between them that she does.
Now, as a deadly magic and the threat of war loom over them both, Aruna is the only person standing between her and death at the hands of his bloodthirsty kin.

As the two of them grow closer, Novikke wonders: Would a night elf ever betray his own people to protect a human?