Summoner The Complete Collection 4 Books Box Set by Taran Matharu (The Novice, The Inquisition, The Battlemage & The Outcast)

From Book 1:
He can summon demons. But can he win a war?
Fletcher is working as a blacksmith's apprentice when he discovers he has the rare ability to summon demons from another world. Chased from his village for a crime he did not commit, Fletcher must travel with his demon, Ignatius, to an academy for adepts, where the gifted are taught the art of summoning.
Along with nobles and commoners, Fletcher endures grueling lessons that will prepare him to serve as a Battlemage in the Empire's war against the savage Orcs. But sinister forces infect new friendships and rivalries grow. With no one but Ignatius by his side, Fletcher must decide where his loyalties lie. The fate of the Empire is in his hands.