E.J. Tett

Immortal Allery Locke has been tasked with finding the key that opens doors to other dimensions. Find it and hand it over to the wardens for destruction. There's only one problem-the key is a woman. Whenever the key-Deni-opens a door, it allows monsters, demons, and all manner of unsavoury supernaturals to cross over and wreak havoc. Allery must keep Deni from falling into the wrong hands, because if rogue wardens get hold of her, it will cause an interdimensional war.
Can Allery make the impossible decision? Kill her lover, or risk the end of the world.