The Cruelest Gift by David J. Stuart

A prosperous nation abandons the impoverished. A world of love and wonder besieged by a hateful cult. An uncharted paradise bears a terrible curse. To bring the lands together, she must tear herself apart.

When Ana Blufelt, arguably the most powerful spellslinger in Tabaria, is offered a divine quest promising vast riches, she can't resist. Setting out with her three fellow mercenaries to what appears to be a blissful paradise, success is almost certain.

Almost.

Meanwhile, Tabaria finds itself mysteriously losing people left and right. Social unrest flows through the streets like oil, and a shadowy, bigoted death cult has struck the match. And the royal family has tasked Ana to keep Tabaria from burning to the ground.

But first she must do something about this dead girl following her around.