The Mythean Arcana, book 5: Fate UndoneLinsey Hall2015

A god in disguise No one in the Prison for Magical Deviants knows that prisoner Logan Laufeyson has a secret identity. He is the ancient trickster god Loki, in magical disguise on a mission of his own. A mission that will come to a sudden and disastrous end… The woman he's never forgotten Demi-goddess Sylvi has spent eight hundred years trying to forget her long-ago affair with Loki, which destroyed her dreams and got her banished from her home. When Loki escapes from prison and stumbles through her door with a problem that threatens both their lives, she must set aside her anger while trying to resist a passion she’s never forgotten. The fact that her magic can be enhanced by sex makes ignoring Loki even harder — especially when they must utilize her rare talent. The plan of ultimate evil Thrown together, Loki and Sylvi must foil a masterful plot that threatens not only their lives, but every god in existence. It will take all of their power, and all of their long-buried love, to face the ultimate danger - or vanish and be forgotten forever…