Fallen Prince (Fallen Trilogy book 1‪)‬

She’s the perfect princess, he’s the resident bad boy, they’ve always had each other. Their loyalty is about to be tested.
When the peaceful kingdom of Shaundakul is betrayed by its allies, Princess Ellia Solidor and her protector, Cyric Dracla, are taken into slavery to the kingdom of Akadia. Their only goal is to stay safe, and stay together. But in this new land that values power over everything, all Ellia can see is the captivity of her people, while Cyric sees a chance to finally become the great warrior he was never allowed to be. Temptation becomes betrayal, and Ellia must travel to the legendary Isle of Yanartas to gain the ability to defeat the dark power her best friend has become.
Fallen Prince is book one of the Fallen Trilogy. The adventure continues in book two, Fallen Kingdom.