Doom Helix — James Axler

Devastation from the nukewar shattered civilization and left a planet both primitive and ripe for rebirth -- or retaking. While the balance of power has fallen to avaricious, amoral barons, a handful of humanity still holds hope of a future worth fighting for or dying to defend. If a better life inside the hellground exists, Ryan Cawdor and his friends will find it.

The Deathlands feudal system may be hell on earth but it must be protected from invaders from Shadow Earth, a parallel world stripped clean of its resources by the ruling conglomerate and its white coats. Ryan and his band had a near-fatal encounter with these genetically enhanced aggressors and their advanced weaponry and wags once before. Only a fatal chink in enemy armor saved planet Earth from plunder. Now, these superhuman predators are back, ready to topple the hellscape's baronies one by one.