The Stormcaller by Tom Lloyd

Isak is a white-eye, feared and despised in equal measure. Trapped in a life of poverty, hated and abused by his father, Isak dreams of escape, but when his chance comes, it isn't to a place in the army as he'd expected. Instead, the Gods have marked him out as heir-elect to the brooding Lord Bahl, the Lord of the Fahlan.
Lord Bahl is also a white-eye, a genetic rarity that produces men stronger, more savage and more charismatic than their normal counterparts. Their magnetic charm and brute strength both inspires and oppresses others.
Now is the time for revenge, and the forging of empires. With mounting envy and malice the men who would themselves be kings watch Isak, chosen by Gods as flawed as the humans who serve them, as he is shaped and moulded to fulfil the prophecies that are encircling him like scavenger birds. The various factions jostle for the upper hand, and that means violence, but the Gods have been silent too long and that violence is about to spill over and paint the world the colour of spilled blood and guts and pain and anguish . . .

This book is part of the "Twilight Reign" series.
Here are some other books from this series: