We Hunt the Flame Novel by Hafsah Faizal

Zafira is the Hunter, disguising herself as a man when she braves the cursed forest of the Arz to feed her people. Nasir is the Prince of Death, assassinating those foolish enough to defy his autocratic father, the sultan. If Zafira was exposed as a girl, all of her achievements would be rejected; if Nasir displayed his compassion, his father would punish him in the most brutal of ways. Both Zafira and Nasir are legends in the kingdom of Arawiya--but neither wants to be.

War is brewing, and the Arz sweeps closer with each passing day, engulfing the land in shadow. When Zafira embarks on a quest to uncover a lost artifact that can restore magic to her suffering world and stop the Arz, Nasir is sent by the sultan on a similar mission: retrieve the artifact and kill the Hunter. But an ancient evil stirs as their journey unfolds--and the prize they seek may pose a threat greater than either can imagine.