The King has Fallen by Aimee Lynn

It’s extremely inconvenient to fall for your bloodsworn enemy…

Yilan is a Fetch, a skilled female assassin and spy. As the powerful Nephilim sweep across the continent, slaughtering and conquering every nation in their wake, she is tasked with killing their legendary General, Melek Handras.
When Yilan infiltrates the Nephilim camp and allows herself to be captured by these violent creatures, she is brought face to face with her very large, very compelling target.
Melek is uneasy when the female Fetch so quickly surrenders her secrets in exchange for her life. But then the King makes him personally responsible for ensuring she does not escape.
Forced to keep the clever, deadly woman close, he quickly becomes familiar with her scathing humor, and cutting insight. He is forced to admit that Yilan is a woman capable of handling herself, even in his ruthless world… the kind of woman he finds disturbingly desirable.
But war does not wait. Soon, Melek must return to the battlefield to lead his warriors against her people—leaving Yilan in the hands of his brutal comrades who are hungry for nothing more than victory over an enemy.
Especially a very pretty one.

From the #1 bestselling serial author, Aimee Lynn, comes a heavenly new universe in which angels are the enemy, and a thief is the world’s last hope.

Triggers and Tropes include: Dark romantasy, Enemies to lovers, forced proximity, one bed, age gap, he falls first, strong FL, witty banter/narration, slowburn to high spice, and a helluva lot of violence. (PLEASE NOTE: This book includes frequent use of very strong language, and open door love scenes between divinely appointed couples.)
Genre: Romantasy (Fantasy romance series for adults with spice!) including enemies to lovers romance, inspirational / religious mythology, and fantasy romance mates.