Fifty thousand years — hard to believe time could slip by so quickly.
Leo stood naked atop Earth's highest peak, his pale skin stark against the ruinous landscape. Once, long ago, this summit had been a symbol of human triumph: climbers pitting will and flesh against thinning air, bitter cold, and impossible odds just to plant a flag in the sky.
Now, the mountain resembled a corroded skeleton. Centuries of radioactive ash, frozen acid rain, and chemical fallout had blackened the rock into a charcoal husk. Glaciers that were once crisp and blue now lay fractured and tainted, laced with eerie, luminescent fissures where radioactive melt trickled down into poisoned valleys.
Every trace of past expeditions — camps, prayer flags, even the notorious preserved corpses — had long vanished, buried beneath toxic snow or scorched away by relentless radiation. The atmosphere was razor-thin, thinner still after millennia of decay, but Leo no longer needed to draw breath. Any traveler who tried would die of radiation long before suffocation.
Day and night endured in name only. The sky, veiled by a permanent dome of ash and dust, had long since erased the sun and moon from memory, leaving nothing overhead but a dull, endless gray.
Today marked another year. Another thousand-year milestone. And still, no end in sight.
Leo sighed. His mind felt threadbare, worn thin by time, yet his body remained unbreakable. Once, he had come here hoping the thin air — or maybe the isolation — would grant him a mortal end. But death had left him behind long ago.
The planet's radiation had rewritten his biology, preserving the last human in a form that needed poison to survive. As long as gamma-tainted winds grazed his skin or he found sustenance steeped in fallout, he would endure. The mutation hadn't merely stretched his lifespan; it had recast him into something superhuman — strong enough to grind stone into powder, free of hunger and breath, radiant with an energy that turned already-contaminated ground into something even crueler.
Leo pursed his lips and whistled, letting the wind carry a thin, haunting note across the summit. For now, he simply watched the horizon, biding his time; tomorrow, he would descend once more, delving into the planet's last forgotten corners.
Wandering had become a pastime. He spent centuries revisiting waypoints he had flagged during earlier expeditions. Life still clung here and there: stubborn lichen, strange iridescent fungi, a few twisted stalks of half-toxic grass. He never grew tired, so cataloging the world's survivors felt as natural as breathing once had.
In the end, he embraced the role of a lone scientist, chronicling an apocalypse no one else remained to see. He had crossed every latitude, tunneled through the planet's crust, even lingered at the mantle's edge — enduring pressures that should have crushed him to paste — simply because there was nothing left to do but learn what the broken Earth could still teach.
A deep tremor ripped through the peak, dislodging slabs of ice and rock that thundered down the scarred slopes.
"An earthquake?" Leo murmured, lifting one eyebrow but otherwise unmoved. Quakes, radiation storms, sudden volcanic flares — catastrophes were Earth's new pulse. Yet this one carried something unfamiliar: a subterranean hum that reverberated in his marrow.
He glanced downward, as though his gaze could pierce the mountain's crust. Whatever stirred lay far below, in the very heart of the summit he had claimed as home.
Curiosity alight, Leo began his descent with measured steps, following the resonance that thrummed through stone and ice. Far beneath the summit lay a cavern gouged into the mountain's core, a place so steeped in radiation that even he felt its fierce, invigorating burn — though it brought neither pain nor discomfort.
The hollow resembled a vault of humanity's dead ambitions. Reactor cores sat beside warped fuel rods salvaged from drowned submarines and half-melted research labs. Cracked waste casks leaked glittering motes of lethal dust. Deactivated warheads, their casings blistered by time, still pulsed with unstable isotopes. Leo had hauled in blocks of uranium-rich ore, shards of thorium vein, and vials of exotic elements — plutonium-238, americium-241, californium-252 — synthetic fingerprints of a species that had once bent matter to its will.
He treated the chaos like a pantry and trophy room combined, stacking relics wherever they fit. The radiation that would kill any other creature served as his food; this cavern, awash in ionizing glow, felt almost cozy.
At the cavern's heart — where molten metal mingled with gemstones and slag — something gleamed, pulsing in sync with the tremor he had felt above. A crystalline shard, bright as star-fire, thrummed with a cadence that echoed inside his bones. Leo scrambled over mounds of irradiated debris, urgency quickening his stride. For the first time in centuries, he recognized a spark of… what was it? Interest? Hope? Perhaps both.
With one iron-swift punch, he sent a cracked waste cask skidding aside, then stood before the crystal, studying its facets for only a breath before reaching out.
It felt neither warm nor cold, yet a dense current pulsed beneath its surface. Light washed over Leo's skin, turning it almost translucent and exposing the labyrinth of organs beneath — too many hearts, lungs layered three-deep, bone shot through with strange circuits forged by millennia of radiation. He watched, entranced, as the crystal siphoned his power, its glow intensifying with every heartbeat.
"Interesting," he murmured, tilting his head. "It's draining me in… though at this pace, I might outlast the sun."
Almost at once, he sensed the flow widening. The crystal wasn't only feeding on him; it was drawing in the cavern's ambient radiation — the world's poison itself. The realization knocked the breath he no longer needed from his chest.
A low chuckle swelled into full-throated laughter, echoing off the jagged walls. "Magnificent!" He hadn't heard his own joy in centuries, and now it spilled out in a torrent.
"It's refining radiation," he whispered in wonder, eyes shining. The crystal radiated a different energy altogether — purer, gentler, a clean counterpoint to the chaotic fallout that blanketed the planet.
And for the first time in a thousand years, Leo felt something bloom inside him that was dangerously close to hope.