Rise of the Nemesis. Portal Wars, #1

Boren closed the Portal and saved his world. It cost him everything. Ten years ago, Boren sealed the rift between worlds and was left on the other side - stranded in Taytos, a dying realm ruled by godlike tyrants, hunted as the one mortal who dared defy them. He has survived on fury and one desperate belief: that his brother Kleos is still alive somewhere in the ruins. When strange visions lead him into the mountains, he finds what the god-kings have kept hidden for centuries - a prison of dragons, chained and going mad - and a power that might finally be enough to bring Kleos home.
He knows the dragons will use him. He embraces the pact anyway. The bargain remakes him into the Nemesis - an immortal weapon forged from pain, dragonfire, and everything he was willing to sacrifice. The god-kings begin to fall. Rain returns to dead skies. Desperate survivors call him a savior. But each kill blurs the line between man and weapon, and when he finally reaches his brother, what he finds will shatter everything he fought to preserve.
The power that keeps him alive is no longer fully his own. And it may have never been. A dark epic fantasy of god-slaying, moral descent, and vengeance without absolution - perfect for readers of Joe Abercrombie, Mark Lawrence, and Christopher Ruocchio. Start the Portal Wars Saga today - if you dare follow a hero who may already be lost.