Darkblade Series by Andy Peloquin

All in Voramis know the legend of the Hunter. Relentless. Immortal. Death walking. The greatest assassin who ever lived. Pay the master killer his due and the Hunter will execute any target, carry out any contract, no matter how impossible.But when the Bloody Hand crime syndicate harms the innocents under his protection, they foolishly make an enemy of the one man they can’t afford to anger. The price of the Hunter’s vengeance is high—paid in blood and eternal damnation... moreAll in Voramis know the legend of the Hunter. Relentless. Immortal. Death walking. The greatest assassin who ever lived. Pay the master killer his due and the Hunter will execute any target, carry out any contract, no matter how impossible.But when the Bloody Hand crime syndicate harms the innocents under his protection, they foolishly make an enemy of the one man they can’t afford to anger. The price of the Hunter’s vengeance is high—paid in blood and eternal damnation. Not even an army of crooks, cutthroats, and demonic creatures of nightmare can stand in his way. He’s far more than just one man…he’s the Keeper-damned Hunter of Voramis. less

The Hunter is running out of time. And so is all of humanity…The demonic Sage finally has the missing piece in his wicked plan—and with it, the power to free mad god Kharna from his prison. To make matters worse, Hailen’s mysterious and dangerous abilities are dragging him ever deeper into madness. The only way to pull the boy back from the brink of insanity is to unlock the dark, deadly secrets of a city long ago lost to time... moreThe Hunter is running out of time. And so is all of humanity…The demonic Sage finally has the missing piece in his wicked plan—and with it, the power to free mad god Kharna from his prison. To make matters worse, Hailen’s mysterious and dangerous abilities are dragging him ever deeper into madness. The only way to pull the boy back from the brink of insanity is to unlock the dark, deadly secrets of a city long ago lost to time. It’s a terrifying race against time and monstrous foes to save Hailen and stop the Sage from unleashing the mad god of death and destruction. When evil wields unstoppable power, it takes a killer to save the world. less