Lightworld/Darkworld Series by Jennifer Armintrout, Michaela Grünberg

In a time not long from now, the veil between fantasy and reality is ripped asunder—creatures of myth and fairy tale spill into the mortal world. Enchanted yet horrified, humans force the magical beings Underground, to colonize the sewers and abandoned subway tunnels beneath their glittering cities. But even magic folk cannot dwell in harmony, and soon two Worlds emerge: the Lightworld, home to faeries, dragons and dwarves; and the Darkworld, where vampires, werewolves, angels and demons lurk... moreIn a time not long from now, the veil between fantasy and reality is ripped asunder—creatures of myth and fairy tale spill into the mortal world. Enchanted yet horrified, humans force the magical beings Underground, to colonize the sewers and abandoned subway tunnels beneath their glittering cities. But even magic folk cannot dwell in harmony, and soon two Worlds emerge: the Lightworld, home to faeries, dragons and dwarves; and the Darkworld, where vampires, werewolves, angels and demons lurk. Now, in the dank and shadowy place between Lightworld and Darkworld, a transformation is about to begin…. Ayla, a half faery, half human assassin, is stalked by Malachi, a Death Angel tasked with harvesting mortal souls. They clash. Immortality evaporates, forging a bond neither may survive. And in the face of unbridled ambitions and untested loyalties, an ominous prophecy is revealed that will shake the Worlds. less

Once upon a time yet to come, creatures of myth and fairy tale gained entry to the human realm and were expelled with extreme prejudice. Banished Underground, they carved out two kingdoms: the Lightworld of the Fae and their kin, and the Darkworld of demons, werewolves and their ilk. But the boundaries between these Worlds and the Upworld are about to be redrawn...in blood.At a Lightworld royal gala, Queene Ayla announces the betrothal of her daughter, Cerridwen, to a high-ranking councilor... moreOnce upon a time yet to come, creatures of myth and fairy tale gained entry to the human realm and were expelled with extreme prejudice. Banished Underground, they carved out two kingdoms: the Lightworld of the Fae and their kin, and the Darkworld of demons, werewolves and their ilk. But the boundaries between these Worlds and the Upworld are about to be redrawn...in blood.At a Lightworld royal gala, Queene Ayla announces the betrothal of her daughter, Cerridwen, to a high-ranking councilor. Though strategically brilliant, the engagement comes as a shock to Cerridwen especially. Infuriated by her mother s high-handedness, ignorant of her own true origins, she flees the court leaving herself vulnerable to those who would see the Lightworld destroyed. Amid burgeoning unrest, desperate desires become divided loyalties and terrifying mercenaries lurk in the shadowy space between rebellion and anarchy. less

With the immortal denizens of the subterranean Lightworld and Darkworld societies locked in battle, the heiress to the Faery throne is exiled to the human realm above. Accompanied to the Upworld by her mother's most trusted adviser, Cerridwen is bound for Eire and the last Fae stronghold on earth. But even this fabled colony is no true haven... moreWith the immortal denizens of the subterranean Lightworld and Darkworld societies locked in battle, the heiress to the Faery throne is exiled to the human realm above. Accompanied to the Upworld by her mother's most trusted adviser, Cerridwen is bound for Eire and the last Fae stronghold on earth. But even this fabled colony is no true haven. In the absence of the true Fae monarch, the formidable Queene Danae established herself as a ruler - and she does not wish to relinquish her power, especially over the devout Humans who live among the Fae as servants.Torn between her own beliefs and the ideals her mother died for, Cerridwen searches for clues to her destiny - is it on Earth among the Humans, or beyond an ethereal portal, in the immortals' ancestral home? Neither path can avert bloodshed - and the choice may not be hers to make. less