The Edge of Chaos

The Edge of Chaos by Jak Koke is the third novel in The Wilds series.

"On the border of a dangerous, magically unstable area called the Plaguewrought Lands, the leader of a cult seeking the spread of this wild magic and an alchemist who wants to control it join forces and create an elixir that allows pilgrims to survive the Plaguewrought Lands. But only one can succeed. A young man with strange powers and a priestess of the god of death will help determine who."