The Waking World by Jordan A. Moore

“Before there was Light, there were Monsters.”

Joy Carter’s peaceful life is shattered by a letter she receives seven years after her mother’s death. It carries a cryptic message about a Silver Key, an artifact that can open a portal between Worlds. Even more shocking; the letter adds that her mother might still be alive. Joy doesn’t believe it until her home is attacked by a horrible monster, and her childhood friend is kidnapped. In the aftermath of the impossible, she has no choice but to obey the letter’s instructions.

With the help of a reluctant band of bounty hunters and an unlikely Eldritch mentor, Joy sets off in search of the Silver Key and The Cosmic Slayers – a secretive group of people who dared to fight the all-powerful Elder Gods themselves – and won.