Moshui, the Books of Stone and Water, book 1: Dragon in Chains
Daniel Fox2009

Deposed by a vicious usurper, a young emperor flees with his court to the small island of Taishu. There, with a dwindling army, a manipulative mother, and a resentful population-and his only friend a local fishergirl he takes as a concubine-he prepares for his last stand.

In the mountains of Taishu, a young miner finds a huge piece of jade, the potent mineral whose ingestion can gift the emperor with superhuman attributes. Setting out to deliver the stone to the embattled emperor, Yu Shan finds himself changing into something more than human, something forbidden.

Meanwhile, a great dragon lies beneath the strait that separates Taishu from the mainland, bound by chains that must be constantly renewed by the magic of a community of monks. When the monks are slaughtered by a willful pirate captain, a maimed slave assumes the terrible burden of keeping the dragon subdued. If he should fail, if she should rise free, the result will be slaughter on an unimaginable scale.

Now the prisoner beneath the sea and the men and women above it will shatter old bonds of loyalty and love and forge a common destiny from the ruins of an empire.