While the earth groaned under the weight of the Walkers, the heavens remained a graveyard of soot—until the Sky-Shrouds ascended. These were not birds, nor were they kin to the pterosaurs of old. They were atmospheric leviathans, translucent sheets of muscle and gas-bladders that spanned hundreds of feet. They fed on the ionized particles in the upper atmosphere, trailing long, stinging filaments that hung down like the roots of a floating forest. These filaments were miles long, virtually invisible against the grey clouds, acting as a massive, aerial drift-net that captured anything rising from the surface—from volcanic ash to the smaller, winged scavengers that had begun to take flight.
The Gorgon-Walkers below learned to fear the sky. A Sky-Shroud could descend silently, its filaments wrapping around a Walker's neck and injecting a neurotoxin that turned internal organs into liquid slurry. The Walkers responded by evolving reflective scales on their upper backs, designed to bounce the Sky-Shroud's bio-electric pulses back at them. This created a shimmering effect across the plains, as if the ground itself were made of fractured diamonds. Whenever a shadow passed over the sunless land, the Walkers would huddle together, their combined heat creating a thermal updraft that pushed the delicate Shrouds higher into the stratosphere, away from their vulnerable vents.
This aerial evolution changed the planet's climate. The movement of thousands of Sky-Shrouds began to stir the stagnant air, creating the first massive storms of the era. These were not rainstorms, but "Static Tempests"—hurricanes of lightning and dust that lasted for decades. The friction of the Shrouds' massive bodies against the dry air generated enough electricity to light up the night for months at a time. The Gorgon-Walkers had to adapt to a life of perpetual motion, moving with the eye of the storms to avoid being shredded by the atmospheric friction. They became nomads, following the shifting currents of the sky as if guided by an invisible hand.
The dominance of the Gorgon-Walkers was being challenged from above. To counter the Sky-Shrouds, the Prime Alphas developed the ability to hurl "magma-bolts"—projectiles of semi-solid lava launched from their dorsal vents. These bolts would streak across the sky like reverse meteors, tearing through the thin membranes of the Shrouds and sending them spiraling down to earth in a rain of burning jelly. The sky was no longer a ceiling; it was a battlefield. The world was now layered: the burrowers in the deep, the Walkers on the surface, and the Shrouds in the clouds, all locked in a desperate struggle for the dwindling heat of a dying sun.
This three-dimensional warfare pushed biological engineering to its absolute limits. The Sky-Shrouds began to develop gas-chambers that could store hydrogen, making them highly flammable but incredibly buoyant, allowing them to reach altitudes where the Walkers' magma-bolts could not touch them. From these heights, they dropped "spore-bombs"—biological payloads that would bloom upon impact, coating the Walkers in a corrosive slime. The war between the earth and the sky was a stalemate of escalating horrors, each side evolving new ways to reach the other across the void of the atmosphere. The planet was a pressure cooker of biological innovation, and the lid was about to blow.