Warsworn. Chronicles of the Warlands Book 2

Lara is a daughter of kings, a city girl and a powerful healer ion her own right, but she is the Warprize and has sworn an oath of loyalty to Keir, the barbarian Warlord, and his people. As Keir and the tribe are makingtheir way back to their homeland, they come across a village stricken down by plague - and though Lara has the tools to fight this scourge, the Warlord forbids her risking her own life.
Both Lara and Kier are strong-willed and neither will bend easily, even for love. When Lara disobeys, she pays the price, for both she and Keir are struck down by the fatal disease - and so is their entire encampment. In the midst of the dying, a rival warrior gathers his followers and challenges Keir for the right to rule their tribe. If Keir, weakened by sickness, loses - he dies. And so does Lara .