The Blameless by E.S. Christison

Briana, Princess of Predonia, has lived a happy and sheltered life. Then, in a single night, her kingdom is overthrown and centuries of peace are abruptly shattered. Fleeing for her life as her kingdom burns, Brie is rescued by Flinton, Derek, and Kove, three powerful protectors who pledge to teach her how to fight and use the powerful magic that has awakened within her. Brie finds sanctuary in the mountain stronghold of the Blameless, people who receive magical gifts from the gods after performing acts of unparalleled selflessness. Among them, Brie’s grieving heart slowly learns to live and laugh again. With the help of her new friends, she strives to master her growing powers so she can avenge her family, take back her place as the rightful heir to the throne, and free her people from the clutches of a tyrant. But can one girl change the tides against an evil that has conquered an entire kingdom?