Seven Stones: Riders of Flame and Shadow

Dorian was taken in by the Brothers of Eteri when he was a baby after being abandoned in the woods. The brotherhood has trained him in their religion, teaching him to worship and fight in the name of Eteri, the Mother of Dragons. He is sent on a mission to recover a relic from the time of the Dragon Riders. He spends years in Blue Stone, creating a life, forming connections, and searching for the relic. And along the way, he meets Lex, a young, charming, and wounded soldier who likes cheap booze and pretty women. They form a friendship and start working the streets of the underground market, The Barden. When he finally learns of the relic, still unsure of its exact nature, Dorian and Lex embark on a life-changing journey to find it.
What he doesn't know until it is too late is that Nisha, an Umbra, assassin and witch, and daughter of the Red Witch, is also after the relic. When Nisha and Dorian fight for the object, a magical "accident" occurs, binding their destinies in a way that could very well alter the future for all of Seven Stones. When the accident reveals they are bonded to the last twin dragons in Seven Stones, they both have a decision to make: stay bonded, foregoing their mission, or be the first dragon riders in over a millennium.