The grand architecture of the kill-box was complete. The stage was set, the pathways defined, the sightlines perfected. Now came the intricate, patient work of stringing the instruments of the orchestra. For two more nights, Zero became a craftsman, a weaver of deadly, silent threads, translating the grimoire's arcane, bloody text into the cold, hard reality of iron, oil, and stone.
His first and most ambitious project was the chains. The three lengths of heavy, pure-grade iron anchor chain were a testament to Kael's resourcefulness. Each link was as thick as a man's wrist, the iron a dull, non-reflective black that seemed to drink the light. They were incredibly heavy, each length a monumental effort for his F-Rank body to drag from the antechamber into the main experimentation chamber.
He spent the better part of a night in the high, dusty rafters, a place of vertigo-inducing drops and precarious, rotting timbers. Here, his past life as a porter, a creature accustomed to heights, heavy loads, and the grim calculus of leverage, paid dividends. He used a length of rope and a corroded but still-functional pulley system, a relic of the alchemists, to haul the first chain into the ceiling's superstructure.
He did not simply hang it. He rigged it. He found a massive, central support beam, one he had already subtly weakened with his crowbar, and made it his anchor point. He draped the three chains over this beam, their immense weight held in place by a simple, but ingenious, trigger mechanism: a single, thick timber, wedged perpendicularly against the beam, holding the chains in a state of perfect, coiled tension. A single, sharp, kinetic blow to the end of that timber would dislodge it, releasing all three chains to fall simultaneously into the center of the room below, a sudden, inescapable cage of pure, quantum-destabilizing iron. It was a deadfall trap, but instead of crushing its victim, it was designed to pin a ghost to the mortal plane.
With the chains in place, his attention turned to the floor. He retrieved the heavy sacks of finely milled iron filings. This was the most delicate, painstaking part of his work. He was not a warrior sowing salt; he was an artist, drawing invisible lines of death. He poured the fine, dark grey powder into his hand and began to walk the perimeter of the kill-zone.
He didn't create a simple circle. That would be too obvious, a clear declaration of a trap. Instead, he used the natural features of the room. He sprinkled a thin, almost invisible line of the filings across the main threshold, the one clear path he had created. He filled the cracks between the flagstones in a wide, sweeping arc around the central, cracked obsidian ring. He used the dust and debris on the floor as camouflage, making the fine, metallic powder indistinguishable from the grime of a century.
To any normal person, the room would look unchanged. But to a creature like the Glimmer-Hulk, it was now a minefield. These were not just lines of dust; they were metaphysical razor wires, designed to shred the creature's chaotic cohesion, to bleed its unnatural energy with every step it took inside his chosen arena. It was a war of attrition, and he had just weaponized the very ground his enemy would walk upon.
His final task was the most direct, the most primal. The flasks of oil.
He placed them with a strategist's precision. Not in a single, large pool, but in a distributed, overlapping pattern. He placed three flasks in the rafters, wedged precariously above the spot where the chains would fall, designed to shatter on impact and douse the trapped creature in flammable liquid. He placed another three in a wide circle on the floor, hidden amongst the rubble, their corks removed, their contents slowly seeping into the surrounding debris, creating a network of highly combustible "hot spots."
The last six flasks he kept for himself, arranging them in his chosen vantage point—a high, shadowed alcove on the far side of the chamber, a place that offered a clear view of the entire kill-box, a direct line of sight to his chain-trap trigger, and a secondary escape route through a small, crumbling ventilation duct.
As he worked, a strange, profound sense of calm settled over him. The [Callous] skill was more than just an emotional shield; it was a lens of pure, unwavering focus. The ghost of Ashe, with its moral quandaries and its panicked, human fears, was a distant, silent observer to this cold, intricate work. There was no revulsion at the grim nature of his task. There was only the quiet, professional satisfaction of a master craftsman seeing his creation take shape.
Every placed flask, every line of iron dust, every tested link of the chains, was a verse in a grim, silent poem he was writing. A poem of vengeance, yes, but also a poem of control. The Glimmer-Hulk had shown him chaos. It had shown him the terrifying, unpredictable nature of a power that obeyed no rules. And his response was this: a perfect, interlocking system of traps, a machine of pure, unforgiving logic. He was answering the beast's chaos not with his own, but with its absolute and utter opposite.
On the final night of his preparation, he stood in his alcove, his perch, and looked down upon his finished work. The main chamber of the Alchemist's Maw was no longer a ruin. It was a chessboard, and every piece was his. The clear, inviting path was the gambit. The noise traps were the pawns. The iron filings were the bishops, controlling the diagonals. The oil flasks were the rooks, waiting in the corners. And the chains, the heavy, silent chains hanging in the darkness above, they were the queen, the single, decisive piece that would deliver the checkmate.
He had done everything he could. He had studied his enemy, learned its weaknesses, and designed a perfect, bespoke trap to exploit them. He had turned a crumbling ruin into a monument to his own cold, analytical rage.
The silence of the sub-basement was a heavy, expectant thing. The air was thick with the scent of old stone, of dust, of oil, and of a profound, waiting violence. All that was missing was the final, critical component. The prey. The stage was set. The traps were laid. The kill-box was perfect. Now, all he had to do was send the invitation.