The Death King by Jovee Winters

Hades is the Dark King of Legend, the god of the Underworld and the master of death itself. Calypso is a wild, capricious, and ancient goddess more powerful than all the gods of Olympus combined. Theirs was a legendary love until a curse came and tore through Kingdom and with it the end of all they’d once been. Without her he is lost and without him, she’s lost her way.
In the new world, Calypso remembers little of who she’d once been, but Hades remembers it all. And the agony of her loss is slowly killing him. But the Dark King refuses to lose at anything. He will get his dark priestess back, he will make her remember him, remember their love, or die trying.

Calypso is an elemental with a dark secret, she’s dual-natured and now, thanks to the curse, that dark side of her she’d long suppressed is awake and ready to blaze a path of terror and destruction through all the worlds. And she’ll do it too…except a man with dark, starlit eyes has suddenly begun to haunt her dreams. She’s remembering things, things that couldn’t possibly be. Things like touches, whispers, and seduction.
But she’s a virgin goddess, untouched, unspoiled by the hands of another, or is she really? Who was she in the before? In that once upon another time? That’s what Calypso aims to find out, and when a wild elemental makes a plan nothing and no one can stand in her way…