Cold Moisture

The air tasted of dead snow before the dust even settled.

In Oshuro, cold was not a season. It was an execution. When the northern basalt wall gave way, forty winters of trapped glacial ice poured through the breach, turning the heat-shimmer over the Upper Terrace into gray, tumbling sleet.

I did not waste time looking at the sky. The sky never paid for blades.

I grabbed my heavy oiled-leather kit from beneath the bench. My geothermal vent was already wheezing, its cherry-red throat fading to a dull cinder as arctic drafts poured down the chimney flues. Obsidian was glass. If volcanic glass cooled too fast under uneven drafts, internal tension built along the microscopic stress paths. A single tap would turn a masterwork core into ten pounds of useless black gravel.

I moved down the cooling rack with practiced speed.

I bypassed the rough blanks and the half-flaked scrapers. I reached straight for my six prime cores—dense, coal-black nodules mined from the deep magma roots near the caldera's floor, free of air pockets or sulfur streaks. Each had spent three uninterrupted days soaking in the flue's dry heat.

I wrapped each core in three layers of greased sheepskin, securing the bundles with boiled-leather thongs. The grease kept the ambient moisture out; the thick wool held the stored heat in. Six cores. Six chances to knap proper thermal edges once I found an active vent lower down the crater.

Outside, the first screams echoed down the stone stairway.

Heavy boots slammed against the basalt steps. The timber door of my workshop shuddered, then banged open on its copper hinges.

Yamato stumbled across the threshold, dragging his left shoulder against the doorframe. He had survived twenty paces up the avenue before turning tail.

"They're coming through," Yamato wheezed. His thick face was smeared with gray mud, his breath pluming in thick white clouds. "The upper barricade broke. It didn't even hold for ten breaths."

I tied off the knot on the sixth core and slotted it into my travel harness. "You still have my daggers?"

Yamato raised his trembling fists. The matched obsidian daggers were still gripped in his calloused hands, but their violet heat-soak had dimmed to a sickly, pale lavender. Frost clung to the knuckles of his grip wraps.

"They didn't work, Tadashi," Yamato stammered, panic pitching his voice into a raw rasp. "Kura's boys charged the first three raiders at the landing. Kura brought his great-blade down clean on a vanguard's shoulder. A perfect strike. And the glass just... it died. It snapped like frozen tallow."

"Obsidian doesn't snap unless you hit stone or let it freeze," I said, slinging the leather roll over my shoulder and grabbing my copper-weighted bone billet. "Did you strike armor?"

"No armor," Yamato said, backing out toward the street as shouts and crashing timber multiplied outside. "They aren't wearing boiled hide or bronze plates. They're wrapped in wet fur. Soaked in slush from the glacier wall."

I stepped out through the doorway onto the narrow landing of the Third Terrace.

The crater had turned into an abattoir of steam and ash. Freezing wind whipped down the stepped terraces, carrying needles of sleet that hissed violently wherever they struck hot stone. A hundred paces up the central staircase, two dozen terrace defenders had formed a desperate wall around the secondary flue junction.

Opposing them were thirty raiders in tattered, dripping furs. They were gaunt men with sunken eyes and frostbitten cheeks, their limbs wrapped in sodden pelts packed with crushed ice and freezing mud. At their head stood a tall commander in an elk-skull mantle, barking concise commands that cut cleanly through the chaos. Commander Soshi. His vanguard moved in tight, disciplined ranks, locking their slush-caked shields together as they pressed up the terrace steps.

Four pit fighters from the Second Tier lunged up the stairs, swinging heavy thermal broad-knives. The blades flared with bright orange heat as their owners struck the flint striking-bosses together, intending to release a scything wave of superheated glass-planes.

"Watch the angle!" I muttered under my breath.

The lead defender swung his thermal blade directly at a raider's chest.

The raider did not parry with steel. He simply shoved a wicker shield forward—a rough frame plastered with a four-inch crust of frozen glacier slush.

The glowing obsidian blade bit into the slush.

There was no clean thermal cut. There was only a sharp, violent hiss of steam. The extreme thermal gradient between the volcanic glass and the zero-degree slush acted instantly. Cold moisture wicked into the micro-fissures along the blade's edge. The conchoidal matrix underwent thermal shock in a fraction of a second.

Crack.

The broad-knife detonated into thousands of blunt, harmless black shards.

Before the defender could recover his balance, the raider drove an iron-tipped spear through his throat. The defender collapsed backward into the red mud, blood bubbling over the slush.

"See?" Yamato croaked beside me, his bulk trembling. "The glass is cursed. The frost eats the fire."

"The glass isn't cursed, you idiot," I snapped, tightening the strap of my harness. "It's physics. Thermal obsidian stores dry heat. If you drive a four-hundred-degree conchoidal bevel into freezing slush, the expansion differential shatters the edge before the cutting plane can form. They know our metallurgy better than our own fighters do."

Soshi's men were deliberately weaponizing the glacier's meltwater to nullify Oshuro's only technological advantage.

Down in the thoroughfare, another pair of defenders tried to flank the raiders. Soshi did not even look at them; he pointed two spearmen toward the left flank, while he led the main body of his vanguard straight down the central avenue.

They marched straight past the storehouses, granaries, and slave pens, following the thick basalt conduits that channeled geothermal steam from the caldera floor to the upper district.

"They aren't looting," I said, my chest tightening as the draft chilled the sweat on my neck. "They're hunting the main flues."

"Why the flues?" Yamato asked, his teeth chattering. "The flues are too hot to sleep in."

"Because if you hold the flues, you hold the air," I said. "If Soshi caps the secondary vents, the Upper and Third Terraces freeze solid before midnight. Every fighter above the rim dies without a single thrust of an iron spear."

Soshi's vanguard cut down the last two defenders at the landing. One of the raiders turned, his pale, frost-rimmed eyes locking onto the leather tool-roll across my back and the bone billet in my hand.

He raised a dripping spear and shouted in a guttural northern dialect.

"Run, Yamato," I said, backing toward the narrow stone chute that dropped toward the Fourth Terrace. "Unless you want to find out if your daggers cut better when they're cold."

Yamato did not need to be told twice. He turned his heavy frame and bolted down the dark stone tunnel.

I took one last look at my workshop. Frost had already crept across the threshold, riming my knapping bench in white crystals. My home was gone, but the six cores against my ribs were still warm. I dropped into the darkness of the descent chute just as an iron spear clattered against the basalt doorway.