A Reign of Rose by Kate Golden

From Kate Golden, author of viral phenomenon A Dawn of Onyx, comes the unforgettable, epic conclusion to her pulse-pounding Sacred Stones trilogy.

They must save the world—but can they also save each other?
 
Kane Ravenwood, King of Onyx Kingdom, would go to the ends of the continent for Arwen Valondale, but what if she’s beyond even that? Broken in ways he never imagined he could be, Kane must survive to fulfill the prophecy and kill his father, Fae King Lazarus. After what he's endured, Kane is willing to save all of Evendell by whatever means necessary—even if that spells his own death.
 
Little does Kane know, he's not the only one desperate for revenge. Arwen is no longer afraid to fight—no sacrifice is too great, no enemy too daunting. Now, nothing will stop her from destroying Lazarus. She’s all too aware that if she fails, both realms will be doomed forever.
 
With the help of new allies and old friends, Kane and Arwen will see this battle through to the end.