Ashen Son by Carissa Broadbent

Maxantarius is a skilled magic Wielder and a military rising star. But in one terrible night, he has learned that glory is bloodier than he ever could have imagined.
War has broken out, thrusting his family into the center of a savage conflict. In its wake, Max is chosen to compete for the title of Arch Commandant.
The title is all he has ever wanted. But the competition is merciless, and victory will mean fighting against the love of his life… all while he must navigate a war that threatens to destroy those he treasures most.
As allies and enemies alike draw blades at his back, Max learns that no victor walks away with clean hands.
It’s only a matter of how far he’s willing to go.