Here is a list of The Empire Trilogy Books Ranked, According to Goodreads.
#1 – Mistress of the Empire (4.34)
#2 – Servant of the Empire (4.32)
#3 – Daughter of the Empire (4.29)
From the blurb:
Magic and murder engulf the realm of Kelewan. Fierce warlords ignite a bitter blood feud to enslave the empire of Tsuranuanni. While in the opulent Imperial courts, assassins and spy-master plot cunning and devious intrigues against the rightful heir. Now Mara, a young, untested Ruling lady, is called upon to lead her people in a heroic struggle for survival. But first she must rally an army of rebel warriors, form a pact with the alien cho-ja, and marry the son of a hated enemy. Only then can Mara face her most dangerous foe of all—in his own impregnable stronghold.…