A Confederacy of Dragons by Katie MacAlister

Phyllida Hall is both the rarest and yet least sought-after member of the Otherworld, bound by a prohibition that limits her magic. Tormented by a former lover, she lives in quiet solitude…until an upheaval makes her one of the most overpowered beings alive. Desperate to hide from those who would use her, she dreams of a man who can help her survive.
Bastian Blu has more than enough on his plate as wyvern of the blue dragon sept, but just when he thinks he has a handle on it, the First Dragon names him a dream warrior, bestowing him with powers beyond his understanding…and which end in death. Now Bastian is suspicious when ouroboros dragon tribes wave a flag of truce, but it’s Phyllida who restores sense to the insanity that surrounds him.
When a half-dragon named Xavier forces Bastian into a choice that can only end in tragedy, will he claim the love that has eluded him his entire life, or become the dream warrior he was born to be?