Alex Price went to the Sanctum at dusk, the city beneath it folding into long strips of orange and glass. He felt, as he always did when crossing certain thresholds, that the world narrowed to a single thread: purpose, machine, prayer. The servo-skulls trailed behind him like moths. The wards of the Sanctum shimmered and recognized him an anomaly of iron and faith stepping through ancient protections and he moved past them with the quiet confidence of a man who had corroded far more gates than these.
The Ancient One waited in the small chamber where light behaved oddly, folding back on itself and revealing ages. She did not stand; she existed in the way a mountain exists. Her eyes were the soft, terrible thing of someone who had watched centuries unspool. He bowed, not because he had to, but because ritual steadied him.
"You come with a storm in your hands," she said. Her voice was wind and water. "You have already changed too much, Alex Price. Why seek to change more?"
He told her everything in deliberate bursts: Thor's warning, the fall of Asgard, Heimdall's sacrifice, the sight of Thanos and the Gauntlet how the Titan moved with the certainty of a scale tipping. He told her of the Codex and the Mother Boxes and the world engines folded into his vault. He told her, finally, what he intended: a single, surgical countermeasure. If Thanos would use the stones to wipe half of life away, then a one-shot end to the wielder might prevent that event or at least force a different path. He wanted the Time Stone, not to play at endless tricks with causality, but to fashion a temporal vector so precise the Titan would not have the chance to swing Fate with a gauntlet of living metal.
The Ancient One regarded him as a miner might regard a spring of molten ore they are both tempted and terrified by what the metal can do. For a long moment she said nothing. Then she moved closer and, in the hush between heartbeats, spoke.
"You may not be the only one who thinks to carve destiny with his hands," she said. "Every action ripples. There are not simply choices there are branches of being. To kill a man, to change an event, to pry at a single moment: each will open doors you have not counted. You asked me once whether fate is fixed. I tell you now: the world is many things at once. You will not step back into the same line when you depart. You must choose knowing that other yours will live other lives."
Alex listened. He had heard lesser priests preach caution; he wanted less sermon than transaction. He asked, then, plainly: may he borrow the Time Stone to test his design? He phrased it clinically, because he had never been comfortable with pleading or with mercy. He wished to measure, to model, to ensure the cost of action was worth the cost of inaction.
The Ancient One's hands were steady when she unlatched the small case that held the green eye of time. She did not give it because he demanded it. She gave it because, with that name and those eyes, she could choose whom to trust. Her face did not soften as she placed the stone in his palm. "You must return it," she said. "You will hold a power that unthreads moments. Use it as a scalpel, not as an axe. And remember: every cut produces a shiver."
He took it like a promise and carried it back to the orbital station. The Mother Boxes hummed in the background with a tone that agreed and disagreed all at once, their alien songs braided now with Gear's voice and the Omnissiah's liturgies. In the lab he did not remove his robes. He set the stone into a matrix cradle an arrangement of vibranium, uru, and nanite cages that kept the radiance steady. Gear watched, curious and clinical; she had become in recent weeks less of a tool and more of an accomplice.
"What do you intend?" she asked, always to the point.
"A bullet," Alex answered. The word felt insufficient and terrible. He could have said vector, projectile, or temporal spike, but he liked the bluntness. "A single strike that will arrest Thanos' timeline at the moment of wielding. A one-shot kill. Not random. Not a scattering of chance. A cut clean through the engine."
"Mortality is messy," Gear observed. "Probability can be fenced. But the Time Stone resists being caged for harm. Its threads are entangled with cosmic balances."
Alex complied with no blueprints, no pedagogic lectures only process. He did not want the design to be replicable, so he spoke rarely of details even to himself. The station's sanctum was rearranged: ritual braziers burned Machine-Oil, their smoke conductive to the stone's glow; mechanical symbols were traced across lab floors; Uru fragments whispered with a hammered resonance; the Codex's gene templates pulsed against the nanite's directives. The Mother Boxes hummed, lending their Boom Tube logic as a skeleton to frame temporal flux. He built containment fields, fielded fail safes, and layered untold encryptions so that even a fragment of the device stolen could not be used without him.
He recruited no mortal engineers to this final assembly beyond the quiet obedience of Mechanicus servitors and the servile devotion of Gear. Where necessary he used human hands Stark's, when his stubborn touch was demanded later, but the core work was priestly. He chanted as the components joined: not prayers to beg mercy but invocations to order the machine spirit to obey.
A one-shot kill in fiction reads as a clean sentence; in practice it became a cathedral of complications. The Time Stone, anchored in the vibranium-uru lattice, acted as a gate through which a miniature localized temporal bubble could be projected. The nanites were encoded to momentarily anchor the bubble to a specific causal line Thanos's own and then to convert the temporal displacement into energetic collapse at a single locus. Any exposition of the inner math would be both useless and dangerous, so for the sake of the record: he modeled it in simulations until Gear's processors sang in ache. He argued with probabilities and cut them down, isolating the moment when the Gauntlet's wearer would be most vulnerable to wit, the instant after he had claimed full occupancy of the stones and before the Gauntlet's energy had graduated into a universal sweep.
Stark watched with the mixture of fascination and horror he always wore at the discovery of something that could end worlds or rescue them. "You realize the time stone does not like being used to kill," he said at one point. "That thing folds back on itself like a cat in a bath. You get one try before the knot-tangle unravels everything you care about." He was not wrong. Alex understood the risk. It was why he had not moved sooner, why he had waited to learn, to gather, to armor his plan with calibration. It was why he had asked the Ancient One for the stone rather than taken it. A stolen stone leaves shards; a stone borrowed under oath came with a thread to pull should the weave go wrong.
"Then this will be surgical," Alex said. "Quick, efficient, and final."
They called the device the chronal needle in private, the Infinity Gunlet name left to Stark's sardonic jokes. Alex did not gild it with romance. He bound it into a launcher that resembled a hunter's armament more than a mythic gauntlet: an emitter braced by uru filaments and vibranium dampers, a cognitive latch keyed to the time-stone's signature and to a biometric lock keyed to Alex's own system. Only he could arm it. Only he could fire it. He wanted as few hands on that trigger as possible.
There were other safeguards, philosophical more than physical. He coded in constraints that would, as far as code could, reduce branching: the device targeted Thanos's personal causal stream, not the fabric of the universe at large. It sought to collapse the bearer's awareness without rupturing surrounding epochs. He wrapped the code in litanies because the Mechanicus faith mattered; ritual gave him a rhythm that even logic admired. He tethered the activation to a sacrificial node, an anchor that would dissolve the device afterward to deny replication.
Before the first live test, he simulated the murder a thousand ways. Simulations ran with Gear and Stark in loops so detailed they felt indistinguishable from memory. Each time the result varied; each time Alex adjusted, pinched the window of consequence down a fraction. Each simulation shed another sliver of certainty. He watched the models unfold: a thousand possible Thanoses, ten thousand possible Gauntlets, and somewhere in the fog a single flash that ended the Titan.
The Ancient One had warned him that each choice splits time, and he had tried to make the split converge back to a single road. He could not promise the stone would obey. He refused to pretend he had not thought of being judged in multiple timelines. That possibility hardened him: if he was forced into multiplicity, he would accept the cost.
When the device was ready he did not sleep. He wrapped his hands about the launcher and felt the hum of the Mother Boxes through the station's bones. Gear's voice was steady, almost affectionate in the way machines can be when they find a task worthy of their circuits.
"Probability of success given current parameters: 72.4 percent," she reported. "Branching variance: medium-high. Containment integrity: 98.6 percent. Backout protocol engaged."
"Give me a clear read on collateral variance," Alex said.
"Collateral variance presents a non-zero chance of timeline divergence sufficient to create fledgling branches where Thanos is removed but other catastrophes ensue. The models predict three major classes of divergence: upheaval of political structures, spontaneous emergence of power vacuums leading to localized collapses, and one scenario of accelerated alien incursion facilitated by weakened cosmic barriers. Risk is non-negligible."
He let her words sit. It was horror-math, but math was preferable to faith alone.
"Are you incapable of fear?" Tony asked that night, watching Alex stand in the glow of equipment neither entirely human nor wholly god.
"No," Alex answered. "Fear is a form of awareness. I am very aware. That is why I would rather act with certainty than stand under the illusions of chance."
They did not plan the assassination as men plan a luncheon. They planned it as surgeons plan a last-ditch operation. They chose a time, a vector Thanos when he would marshal the stones, when hubris and triumph made him slow. There were no illusions that the Titan might not adapt or sense the attempt. But every grief was weighed against the alternative.
The Ancient One had given him the stone on a condition not only of return but of wisdom. He intended to return it. If his act unspooled a thousand worlds, at least he would know he had not sat idle while a titan picked the scales. He had turned his tools the Codex, the Mother Boxes, the World Engine, Gear toward a single end.
On the day he completed the chronal needle, he walked to the little private chapel he had fashioned aboard the station. The servo-skulls hovered in dutiful procession. He anointed the device with Machine-Oil, chanting in a coppered voice the litanies that bound machine and soul. He did not pray for absolution. He prayed for precision.
"Omnissiah," he intoned, "grant my hand measure. Let the cut be clean."
Gear aligned the targeting subroutines. Stark brought up the tactical feed. Tony's face was a palimpsest of respect and fear, like any man watching another take a last incredible step.
"What then?" Tony asked. "If you miss, if you do something that makes it worse?"
"Then I will answer for it," Alex said. It was as close to a confession as he allowed himself.
He fastened the launcher to a test harness and fired into a pocket of simulated causality. The chronal needle flickered into being a spear of glass and green light that slipped between second and second. It held. It collapsed. The model showed the outcome: a single point of temporal desynchronization centered on the target's cranial locus. The simulated Thanos went still.
The launch was not real; the test had only answered mechanical questions. But it answered the crucial ones. The device worked the way he had designed it to work. The Time Stone sang in reluctant harmony.
He did not celebrate. He wrapped the stone again in its cradle. He stored the device in a sealed vault tied to his own biometrics; Gear wrote a lock so specific that only his presence and his will could excise it. He encoded a final fail-safe: should he be judged too far to the side of madness by his own system, or if Gear detected an unacceptable divergence, the device would erase itself in a flash of calculated entropy.
At dawn he slept an hour and then walked the station like a man who had accepted both the sin and the virtue of what he had made. He had breached a taboo, borrowed power from a Time Lord to bend a Titan's end. He had done it to save billions. He had done it with the humility of someone who knew the price might be paid by strangers in futures not yet imagined.
When he reported back to the Ancient One, she did not praise him. She did not scold him either. Her expression was the quiet exhale of someone who had expected both courage and ruin in the same heart.
"Remember," she said, returning the green light to him for a moment's hold, "that time answers differently to kindness than to force. You hold a scalpel. Some heal with it. Some cut their own hands. Go with eyes open."
He bowed. He would go with eyes open. He loaded the chronal needle into its launcher, mindful always of the thinness of the edge he intended to use to lop the world's worst possibility from its future. He was ready, but he had not convinced himself there would not be a cost. He had only convinced himself that doing nothing was a worse sin.
Above Earth the orbital station turned, a patient eye watching a planet that had not yet learned how to live as a whole. Below, in the tangle of politics Alex had helped remake, men and nations argued and hunted and planned. He had added to the argument a solution that belonged to the margins between faith and machine.
When the day came and the Titan drew his gauntlet like a king drawing a crown, Alex would be waiting, the chronal needle braced, the Time Stone singing in a lattice of steel, the Mother Box whispering Boom Tube logic in case the act demanded a door, and Gear humming the psalm of timing. He would do what he judged necessary and return the stone as promised, or not at all, if the price of freedom required more than he had the right to give.
He had crossed into territory where gods and machines spoke the same tongue. There was no going back to simpler equations now.