The Fox and the Bowman by Sebastien de Castell

A young archer bent on revenge against the knight who impoverished his family encounters an enigmatic stranger who promises him a far more potent form of retribution. But when Thomas finds himself hurled by magic to fight battles in faraway lands, he soon discovers that the vengeance his mysterious benefactor offers could change not only one archer's destiny, but that of the entire world.
A masterful short historical fantasy full of magic, archery, and intrigue by the author of the acclaimed Greatcoats and Spellslinger series.