The Tiger's Watch — Julia Ember

Ashes of Gold: Book One Tashi is a spy and killer -- an elite warrior known as an inhabitor -- taught from a young age to use their bond with the tiger Katala. When an enemy force captures the city, Tashi has no option but to escape. Their safety doesn't last long, however. Soon the conquering army arrives at the secluded monastery where Tashi is hiding, needing a place to treat their wounded. It's not long before their leader, Xian, takes an interest in Tashi.  Xian is cold, ambitious, and even cruel -- at least at first glance. But Tashi is skilled at watching and reading people, and they find a softer side to the young commander -- one that intrigues them.  Tashi's loyalties are strained when they learn they have been deceived by the people who trained them, and they must choose between their countrymen and a budding romance with Xian. But fierce Katala faces no such conflict, and she massacres the soldiers she sees as invaders. Xian's men are determined to take revenge against the tiger, but an inhabitor's bond with their animal cannot be severed -- neither can survive if the other is killed.