The journey from the cave to this riverside had consumed three days and nights of ceaseless experimentation. As soon as his transformation had stabilized enough to allow movement, compulsion had taken over.
The compulsion was not emotional. It was structural. A mind rebuilt to process reality as data could not abide operating within an unexplored system. His new form was a machine whose specifications he did not yet understand.
That was unacceptable.
The first hours had been chaos. The world he had always known—grasslands, acacia trees, rocky escarpments, the winding river—revealed itself in layers that his previous consciousness would have found incomprehensible.
Heat signatures glowed everywhere. Small hyraxes, invisible to ordinary vision, burned like faint coals in cracks of distant rock. Insects became moving points of heat against the cooler air. Even the earth itself radiated stored warmth along patterns of density and moisture.
Sound unspooled into bands. Infrasound tremors from distant elephant herds rolled through his bones like slow thunder. Ultrasonic clicks from bats carved delicate filigrees of information in the air, each echo mapping the world in high-frequency outlines. The calls of unseen birds, the rustle of rodents in dry grass, the grinding movement of worms beneath soil—all of it arrived simultaneously.
Smell detonated into a chemical atlas. Every animal carried a unique signature: the iron-salt of fresh blood, the ammoniac tang of fear, the heavy musk of territorial marking, the subtle threads of reproductive readiness. The river had layers—algae, stone, rotting vegetation, and fish.
For a brief period, even with his upgraded architecture, it threatened to crush him. Every vector of reality slammed into his awareness at once.
His mind adapted, and filters constructed themselves. Prioritization hierarchies emerged. Signals were categorized, ranked, suppressed, and elevated. By the end of the first day, he could choose.
Focus here. Mute that. Elevate this band of sound. Reduce that wavelength of light.
The world did not become less. It became ordered.
Day One: Velocity
He chose a flat stretch of savanna—a corridor of packed earth between low scrub and scattered boulders.
He walked it first, marking distance by memory with perfect accuracy.
One hundred paces. Slight incline here. Small depressions there. Rock outcropping at the far end. Sparse acacia roots beneath the surface—possible instability under extreme force.
Then he ran.
The first acceleration was cautious: faster than any human had ever run, but still within a band his older body could have just approached for heartbeats in moments of absolute desperation. It felt effortless. His lungs barely acknowledged the effort. Muscles fired with such efficiency that force translated almost perfectly into forward motion.
He accelerated again.
Biomechanics that had once bound him shattered. His heel bone—now a lever arm more akin to an ostrich's—gave his calf muscles impossible mechanical advantage. His tendons stored and released energy in oscillating waves; his muscles no longer simply contracted but resonated.
He shifted posture. Head lowered. Shoulders tucked. Spine curved into a predatory arch that turned his whole frame into an aerofoil.
The air responded differently.
He felt it as pressure on his skin, in the vibrations along the micro-riblets that now textured his flesh. His drag profile flattened. Turbulence slid away in organized vortices.
Numbers formed in his mind with each stride.
60 mph
120 mph
200mph
300mph
He kept going until the very earth itself began to object after reaching 410mph.
Micro-fractures spiderwebbed beneath the surface of his footfalls and radiated outward. Grass ripped from the soil in sheets. The shockwaves of each impact propagated as low seismic events.
Game animals within fifty meters dropped where they stood—not dead, but stunned, their nervous systems overwhelmed by the pressure differentials ripping through their insides.
He slowed.
Limit discovered.
Not his.
The planet's.
Day Two: Force
Night cloaked the savanna in shadow.
He preferred it that way.
He found a boulder—a granite monolith half-buried in a hillside, its mass at least ten tons. Under starlight, it was just a darker shape against dark surroundings. To his eyes, it was a cold mass distinct from the slightly warmer rock around it, its crystalline structure visible as subtle differences in thermal emission.
He gripped it.
His hands—longer fingers, broader palms, carbon-reinforced bone—sank into minuscule imperfections in the rock. Pressure climbed.
The stone that had withstood millennia of weathering surrendered in seconds. Hairline fractures deepened into visible cracks. The boulder tore free of the hillside with a sound like a mountain exhaling.
He lifted.
Ligaments held. Bone held. Muscles held. At no point did he feel close to any threshold.
He pressed it overhead.
Then he threw it.
The boulder became a crude projectile, tracing a high arc against the stars. It smashed down through acacia trunks, obliterating them, then burst against another rock face in a spray of shrapnel.
He spent hours like that. Testing leverage. Angles. Punching stone. Kicking trees. Ripping stumps from the earth. Each impact taught him something about stress distribution, about how his own tissues flexed and returned, how the fascia webbing across his frame dissipated and rechanneled force.
By dawn, he understood something with absolute clarity:
In any direct contest between his flesh and the materials of this era, his flesh would win.
He had become a walking violation of every ecological balance.
Day 3 Healing
The wound should have killed him.
Acheron stood at the river's edge, staring down at the place where a deep gash should have been his left shoulder—a wound that, on any normal human, would have meant death through blood loss or infection within hours.
The cave lion responsible lay dead at his feet.
The memory of its jaw was still fresh in his nervous system. He could recall with perfect precision the pressure curve of the bite, the exact penetration depth of each tooth, the way the muscle had torn and bone had flexed under the force.
But the wound was already closing.
Not slowly. Not gradually. Not with the slow knitting of tissue over days and weeks that defined normal biology.
It was vanishing.
To any creature operating at normal temporal perception, the sequence would have been invisible:
There is a wound.
10⁻⁴⁴ seconds pass.
There is no wound.
But Acheron's consciousness was not operating at normal temporal perception.
He wanted to see it.
He wanted to understand.
He reached into the very depths of his mind, bypassing all limitations
His neural pathways that already operated at impossible speeds were forced into acceleration that brushed the edge of physical plausibility. Heat spiked in his skull as electrical activity climbed toward catastrophic overload. Any normal brain would have cooked itself into inert protein in less than a heartbeat.
He did not, only because the same impossible process he was trying to observe was repairing the damage faster than it could accumulate.
Consciousness shredded into frames.
He dove past the millisecond, past the microsecond, into the attosecond gaps between moments. Past that, into Planck time—the smallest interval the universe bothered to count.
At this depth, reality ceased to flow. The world didn't just slow down; it stopped.
The river froze into a glass sculpture. Each droplet in the spray held its shape in midair. Dust motes hung motionless in the sunlight, as if painted onto the air. The insects' wings—normally a blur—became stationary plates of chitin suspended mid-beat.
Only one thing moved.
The quantum state of his own flesh.
As he watched it.
From this compressed perspective, the torn flesh at his shoulder was not a continuous wound but a shifting probability field—a shimmering boundary where what-had-been and what-should-be fought a microscopic war.
T = 0: the gash gaped open, and his bone gleamed pale beneath shredded muscle. Blood, already under arterial pressure, surged toward the open air. In this frozen time, the blood looked like a solid red sculpture erupting from his skin.
T = 10⁻⁴⁴s: the quantum Lock registered a deviation at the most fundamental level of his existence, a template asserted itself—a reference configuration of what "Acheron" was allowed to be. The injured state did not match. It was a glitch in the code of his reality. A violation of the parameters set by the golden mist.
T = 10⁻⁴³s: the universe rejected the deviation. The bleeding didn't slow down. It ceased to be. The red fluid that had begun to escape was pulled back through capillary channels that no longer physically existed, their geometry reasserted by the lock. Muscle fibers that had been torn apart were reconnected with surgical precision along their original vectors. Collagen strands flowed like living threads, weaving themselves into exact prior patterns.
Bone reintegrated. Mineral lattices that had been cracked or stressed rearranged into their previous arrangement with atomic exactness. No micro-fracture remained. No evidence of stress lingered.
Any foreign material—hyena saliva, bacteria, dust—was expelled along the vector of minimum-energy rejection. Particles that had been embedded in flesh were simply pushed out of existence in that configuration. They were not incorporated. The lock refused to accept them as part of the template.
From his perspective, it was a sequence:
Tear.
Assess.
Reject.
Reset.
Over and over, at the smallest possible timescale, the universe supported.
By the time his temporal perception drifted back toward something resembling "slow," the injury had vanished completely.
He slowly raised his left arm, rotating the shoulder through every degree of motion. The joint glided with frictionless perfection. Skin stretched and shifted over dense muscle with no tugging sensation, no stiffness, no resistance.
Perfect. Unblemished. Dry. No stain of blood. No ragged edge of half-healed tissue. No scar.
His mind replayed what he had just observed at compressed speed. The instantaneous cessation of bleeding. The categorical rejection of foreign particles. The total reassertion of a single template state.
It wasn't healing.
Biology had rules, and healing took time. Even the fastest regeneration required chemical cascades, enzymatic reactions, and cellular division.
This was not that.
This was a correction.