Dragonfall by Lam

Long-banished dragons, revered as gods, return to the mortal realm in the first in this magical new epic fantasy trilogy from a bestselling author

Long ago, humans betrayed dragons, stealing their magic and banishing them to a dying world. Centuries later, their descendants worship dragons as gods. But the "gods" remember, and they do not forgive. 

Thief Arcady scrapes a living on the streets of Vatra. Desperate, Arcady steals a powerful artifact from the bones of the Plaguebringer, the most hated person in Lumet history. Only Arcady knows the artifact's magic holds the key to a new life among the nobles at court and a chance for revenge. 

The spell connects to Everen, the last male dragon foretold to save his kind, dragging him through the Veil. Disguised as a human, Everen soon learns that to regain his true power and form and fulfil his destiny, he only needs to convince one little thief to trust him enough to bond completely--body, mind, and soul--and then kill them.

Yet the closer the two become, the greater the risk both their worlds will shatter.

Story Locale:Fantasy world

Series Overview: In the romantic epic fantasy trilogy, shapeshifting dragon Everen falls into the human world and finds himself bonded to a thief, Arcady Dalca--but the closer the two become, the higher the chance both their worlds will shatter.