The first Alchemist breached the gate like a nightmare walking.
He was clad from head to toe in heavy, stiff leather that gleamed with a coating of wax. His face was hidden behind a terrifying mask with a long, curved beak, the eyeholes covered in thick glass. He looked like a plague doctor bred for war.
He raised a brass tube connected to the tank on his back.
"Down!" Narcissus roared, shoving a fleeing legionary aside.
A stream of liquid green death hissed from the nozzle. It hit the wooden palisade of the gatehouse. The wood didn't just catch fire; it screamed. The chemical hissed and popped, eating into the timber with a voracious, unnatural hunger.
Chaos erupted inside the fort.
The disarmed traitors were panicked cattle, trampling each other to get away from the green fire. The Alchemists—a dozen of them now, slipping through the confusion—moved with cold, mechanical purpose. They weren't trying to take the fort. They were trying to burn it down with everyone inside.
"Form up!" Titus bellowed, trying to rally his Praetorians. "Shields!"
But shields were useless. An Alchemist sprayed a line of fire across a rank of defenders. The liquid splashed onto their scuta, then ran down onto their hands and legs. Men dropped, screaming as the fire clung to their skin like pitch.
Narcissus, realizing he couldn't get close enough to use his axe, grabbed a heavy pilum from a discarded pile. With a roar, he hurled it. The spear flew true, punching through the leather armor of an Alchemist and pinning him to a wooden support beam.
The Alchemist's tank ruptured.
There was a dull whump, and then a sphere of expanding green flame consumed the Alchemist, the beam, and two unlucky soldiers standing nearby. The explosion rocked the gatehouse, sending burning debris raining down on the defenders.
"Water!" a soldier screamed. "Bring water!"
"No!" Marcus shouted, sprinting from his command tent. "No water! It spreads the fire!"
He had seen the chemical analysis. This was an oil-based accelerant. Water would just float the burning liquid, carrying the fire deeper into the camp.
The fort was becoming an oven. The heat was intense, the smell of burning sulfur and flesh choking the air. They were trapped in a wooden box with a dozen flamethrowers.
Marcus spotted Galen, huddled near the baggage wagons, watching his creation destroy the world. The physician's face was a mask of terror. The reality of his "cure" was far uglier than the theory.
Marcus grabbed him by the tunic, shaking him violently. "Think, damn you! What stops it? We don't have the salt!"
Galen stared at him, his eyes unfocused. "It... it burns until it consumes the fuel. It cannot be stopped."
"Everything has a counter!" Marcus yelled, slapping him. "Think like a scientist! What slows the reaction?"
The blow seemed to snap Galen back to the present. His eyes focused on the green flames licking at the wagons.
"Sand," he gasped. "Sand suffocates it. And... acid. A base to neutralize the acid."
"We don't have baking soda!" Marcus shouted.
"Ammonia!" Galen cried, his mind racing. "Urine! Vinegar! It won't put it out, but it will thicken the oil, slow the burn! The ammonia neutralizes the accelerant!"
Marcus didn't hesitate. He turned to his men, to the terrified traitors, to the Praetorians.
"Gather the sandbags!" he roared, his voice cutting through the panic. "And piss! Everyone! On the blankets! On the tents! Soak them in urine and vinegar from the mess stores!"
It was the most undignified order in the history of the Roman legions.
But they obeyed. Terror is a powerful motivator. Men ripped down wool blankets. They emptied vinegar casks. They relieved themselves in helmets, on cloaks, on anything that could hold liquid.
"Cover the fires!" Marcus commanded. "Smother them!"
A wave of men advanced on the nearest Alchemist, holding heavy, sodden wool blankets like shields. The Alchemist turned his sprayer on them. The green liquid hit the wet wool. It hissed and steamed, the ammonia reacting violently with the chemical fire, turning the liquid stream into a thick, foamy sludge.
It didn't stop the fire, but it slowed it down. It bought them seconds.
"Now!" Narcissus bellowed.
The Praetorians charged. They tackled the Alchemist, burying him under a pile of damp wool and bodies before he could fire again. A sword flashed, and the masked figure went limp.
"It works!" Titus shouted. "Press them! Use the blankets!"
The tide turned. The defenders, armed with nothing but piss-soaked blankets and sandbags, pushed the Alchemists back. They smothered the fires, buried the sprayers, and brutally hacked down the masked intruders.
The last Alchemist retreated through the gate, fleeing back into the darkness of the valley.
"Close the gates!" Marcus ordered. "Bar them!"
The heavy timbers slammed shut. The roar of the battle faded, replaced by the groans of the wounded and the crackle of dying embers.
The fort was safe. But it was smoking, reeking of sulfur and ammonia.
Marcus climbed atop the money wagon, the highest point in the courtyard. He looked out over the sea of faces. His own Praetorians. The disarmed traitors of the Fourth and Tenth Legions. General Varus, standing broken and ashamed in the mud.
Marcus was covered in soot. His armor was stained. He didn't look like a god. He looked like a survivor.
"They burned you!" he roared, his voice raw, pointing a finger at the huddled traitors. "Your 'liberator' treated you like kindling! He sent his ghosts to purge you because you hesitated!"
He let the anger wash over them. "There is no Fourth Legion anymore! There is no Tenth! Valerius burned your eagles! There is only the living and the dead! Who wants to live?!"
A low murmur went through the crowd. Then a shout. Then a roar.
"We do!"
"Then you fight for me!" Marcus screamed. "You fight for the man who didn't leave you to burn! Pick up your swords! We are one army now!"
In the fires of the Alchemists, the civil war in the camp ended. The traitor soldiers, betrayed by their own leader and saved by their enemy, swore a new, blood-oath of loyalty. Marcus had just absorbed an army.
Later, Marcus walked through the camp. The adrenaline was fading, leaving him exhausted. Former enemies were tending to each other's burns. The shared trauma had forged a bond stronger than any political allegiance.
He found Varus sitting alone on a crate. The general looked up. He unbuckled his sword belt and held it out, hilt first.
"I have no honor left," Varus whispered.
Marcus took the sword. "Earn it back," he said, and handed it back.
Crixus approached, dragging a prisoner. One of the Alchemists hadn't died. He was pinned under a heavy beam, his leg crushed.
"We stripped the mask," Crixus said, his face grim.
Marcus looked down. The Alchemist wasn't a man. It was a woman. A young Germanian tribal warrior, her face tattooed with swirling blue lines. Her eyes were filled with a fanaticism that chilled him.
"The Green Fire is just the beginning," she spat, blood bubbling on her lips. "The earth itself will swallow you whole, Roman."
Marcus frowned. "What does that mean?"
Just then, the ground trembled.
It wasn't an explosion. It was a rhythmic, deep vibration that rattled the teeth in Marcus's skull. Dust shook loose from the ancient stone walls of the fort.
WARNING, JARVIS screamed in his head. SEISMIC ANOMALY DETECTED. SUBSURFACE VIBRATION. TUNNELING DETECTED DIRECTLY BENEATH THE FORT.
Marcus looked at the ground, horror dawning. The Alchemists. The fire. It had all been a distraction. A way to pin them in place.
"Get off the walls!" Marcus shouted. "Everyone move to the center!"
But it was too late. The ground in the center of the courtyard buckled.
They weren't safe. The real attack was coming from below.
"We stopped the fire," Marcus whispered, watching the earth crack open. "But we forgot about the worms."