Back at the river, Acheron knelt and let the current wash away blood and fur and filth.
Red drifted downstream in lazy veils, painting the water with the residue of dead lives.
His reflection wavered in the disturbed surface—golden eyes, unmarred skin, a body that had never known a wound.
He knew better now.
Wounds didn't heal quickly.
They never truly existed.
Not in any way the universe would agree to remember.
Every time teeth punctured his skin, every time claws raked his flesh, reality tried to diverge from its locked template. Tried to create a version of him that was damaged, that was bleeding, that was mortal.
Every 10⁻⁴⁴ seconds, that attempt was reviewed.
Rejected.
Overwritten.
Damage could begin. It just could never persist.
Blood moving out of vessels? → Reset.
Foreign object penetrating skin? → Reset. Reject. Expel.
Aging? The slow accumulation of cellular failures over years?
Frozen.
His telomeres would never shorten. His proteins would never misfold in catastrophic ways. His mitochondria would never decay into energy-starved dysfunction. Cellular garbage would never accumulate beyond what his body could sweep away.
He was pinned in a state of perfect vitality by the same law that held the speed of light constant.
There was no off switch.
He had not just gained the ability to survive anything.
He had lost the ability to stop existing.
He sat there as the sun arced overhead. His body didn't cramp. His muscles didn't seize. Hunger signals registered as abstract data, then were automatically corrected away by his rebalancing metabolism.
His mind, though, spiraled.
Time unrolled in his thoughts—not as vague abstraction, but as precise calculation. He watched the trees around him grow, seed, wither, topple, and rot into soil. He watched new trees rise from that soil and repeat the cycle over and over, centuries spinning by like the seconds he now experienced.
He watched the river carve deeper into its banks, changing course millimeter by millimeter, century by century, until the shape of the land itself became unrecognizable.
He watched continents shift. Climates swing. Ice advance and retreat.
Then his mental projection unspooled further into deep time.
Stars burned through their fuel, swelling into red giants, shedding their outer layers. Some collapsed into white dwarfs. Others went violent—supernova detonations that ripped nearby systems apart, leaving neutron stars and black holes in their wake.
Galaxies collided in slow, titanic dances, their spiral arms tangling, their cores merging.
The universe itself expanded. Distances between galaxy clusters grew faster than light could bridge. Islands of matter became forever separated by empty gulfs of dark.
Eventually, the last generation of stars flickered and died. The universe cooled. Protons decayed. Black holes evaporated. The cosmos thinned into a dilute soup of low-energy photons.
Heat death.
No gradients. No structure. No life.
And still, by the rules now etched into the fabric of his existence, he would be there. A single configuration stubbornly maintaining itself in a universe that had otherwise surrendered to maximum entropy.
Alone.
Immortality, in the myths his descendants would one day tell, would sound like a gift.
Sitting by that African river with blood still faint on the air, it did not.
Yet even as that crushing horizon of endless time bore down on him, something else sparked.
Memory of the Alpha Female. Her ragged breath. Her exhausted stance. The look in her eyes when he spared her.
She would live. She would rebuild. She would gather survivors, steal young from weaker packs, raise new generations under the shadow of what he had done. She would encode his existence into instinct and training, turn him into something akin to a god or demon in her kind's primitive understanding.
One day—months, years, or decades from now—she would bring another army to find him.
He felt something that might once have been called anticipation.
He was not just immortal.
He was predatory.
The blood frenzy wasn't a malfunction. It was a feature. Prey stimulus, resistance, coordinated opposition—these things awakened circuits in him that fused the cold clarity of his supercomputer mind with the animal joy of the hunt.
He could hunt forever.
And he would.
The light finally faded. Stars emerged—pinpricks of energy in the vast darkness overhead. The river whispered beside him, indifferent.
He thought of the Alpha Female out there in the dark, limping away from the battlefield. Every labored breath a testament to survival against impossible odds. She would heal. She would remember. She might come for him in months. In years. In some distant season when pups she hadn't yet birthed were mature hunters.
When she did, he would be waiting.
He knew this with the same certainty that he knew the structure of his own bones and the upper limit of his acceleration.
This wasn't a singular event.
This was a pattern.
He would do this again. With other predators. With humans. With anything that could assemble opposition worth testing himself against. He would seed his own future enemies deliberately when chance didn't provide them. Over years and then centuries, he would become not merely an apex predator moving through an ecosystem, but the architect of his own opposition—leaving seeds of hatred, fear, and memory wherever it promised better hunts later.
He was immortal.
He was unkillable.
He was eternally young.
And he was beginning to think like a creature with all the time in the universe.
Acheron lifted his gaze to the stars. His golden eyes caught starlight and seemed to burn with their own internal fire.
What stared out from behind them was no longer human in any conventional sense.
It was something that would outlast the world.
Something that would never stop hunting.
Something that, when given a choice between ending a threat forever and extending the hunt, would always choose the hunt.
Immortality, he realized, was not the destination.
It was the starting condition.
What he chose to become over that endless stretch of time would define whatever the word "Acheron" meant.
For now, he knew three things with absolute certainty:
He could not die.
He would not age.
And one day, somewhere out on the savanna, under some future sky, when the Alpha Female returned with whatever pack she could assemble, he would be waiting.
To hunt.