Curse of the Riftborn

Riftborn Series Book 1:

A serial killer has reigned free in the city of Ebria for longer than anyone could remember. Some claimed it to be a vengeful spirit seeking justice in a city of corruption. Others say it's a powerful undead, practitioner of magic, or worse yet...both. There are rumors it's one person and others saying it's an entire cabal. Many have tried to bring the killer to justice, but for centuries all have failed.
Meira Dyel - a young woman plagued by a lifetime of nightmares is tasked to find the killer when Ryn - her friend and mentor, becomes the latest victim. With the aid of her friend and fellow guildsman Darven, she hunts for the Ebrian Slayer and learns a truth about herself so profound it threatens to unravel her already fragile psyche.