Grievar's Blood

Grievar's Blood by Alexander Darwin
The Combat Codes Saga - Book 2
“He carries the weight of the codes. But the blood on his hands tells another story.”
Tropes: Underdog, Secret Past, Enemey to Brothers, Political Conspiracy
 
In a world where single combat determines the fate of nations, the Grievar fight in the Circles so that the rest can remain at peace. But given the stakes, things are never so simple. The Daimyo govern from the shadows and plot to gain an edge by unnaturally enhancing their Grievar Knights.
 
Cego and his team enter year two at the world's most prestigious combat school, the Lyceum. Though he'd like to focus on his martial studies, Cego feels the pull of his mysterious past and two missing brothers.
 
Solara Halberd, daughter of the fighting legend, embarks on her own quest to bury the past. She must utilize every lesson her father taught her to explore unknown lands where evil lurks in the shadows.