The green fire wasn't just a signal. It was an execution.
From his vantage point on the ridge, Marcus watched the night sky turn a sickly, radioactive emerald. A massive chemical detonation rocked the northern end of the valley, the shockwave rattling the stones of the Etruscan fort.
"What in the name of the gods?" Titus whispered, shielding his eyes against the glare.
Below them, the neat, disciplined lines of the traitor legions dissolved into chaos. The explosion hadn't come from the fort. It had come from behind them. From their own rear guard.
"It's not Crixus," Marcus said, his mind racing to catch up with the horror unfolding below. "It's something else."
Through the smoke and the unnatural green light, strange shadows moved. They didn't march in formation. They flowed like liquid, tearing through the Roman ranks with terrifying speed.
A scream pierced the air, loud enough to reach the ridge. A soldier from the Fourth Legion burst out of the darkness below, running toward the hill fort. He was covered in a glowing green substance. He wasn't burning; he was melting. The fire ate through his lorica segmentata like acid through paper, turning steel and flesh into a bubbling slurry.
DETECTING UNKNOWN CHEMICAL AGENT, JARVIS's voice blared in Marcus's skull, urgent and loud. COMPOSITION SIMILAR TO GREEK FIRE BUT... MODIFIED. HIGHLY CORROSIVE. PH LEVEL INDICATES EXTREME ACIDITY. THIS IS NOT ROMAN TECHNOLOGY.
"Open the gate!" a voice screamed from the darkness below.
A figure stumbled up the steep path to the fort, collapsing against the heavy timber doors. It was a centurion from Varus's camp, his face blackened with soot, his eyes wide with a madness born of pure terror.
"Let me in!" he shrieked, clawing at the wood. "They're burning us all!"
Marcus nodded to Titus. "Let him in."
The gate creaked open just enough for the man to scramble through. He fell to the dirt, gasping, retching.
"Who is attacking you?" Marcus demanded, grabbing the man by his tunic. "Is it Valerius?"
"It's the Alchemists!" the centurion gasped, clutching Marcus's arm. "Valerius's special unit! The Ghost Corps! They don't carry swords, Caesar. They carry... brass tubes. Sprayers!"
He pointed a shaking hand back down the valley. "They didn't attack us. They purged us! They called us weak for hesitating! They're burning the Fourth Legion for failing to attack you!"
The realization hit Marcus like a punch to the gut. This wasn't a battle. It was a friendly-fire massacre. Valerius's inner circle—fanatics armed with science—had turned on their own allies to punish their incompetence. The "Beast" was a rogue unit of chemical troopers.
From the back of the camp, a high, manic laugh cut through the tension.
Galen was standing by the baggage wagon, straining against his chains to look at the green glow illuminating the sky. His face was twisted in a look of ecstatic horror.
"I told you!" the physician screamed, his laughter edging into hysteria. "The fire cannot be controlled! It purges everything! The weak, the strong, the loyal, the traitor! It consumes it all!"
He looked at Marcus with wild eyes. "You wanted a cure, Caesar? This is it! The cauterization of the wound!"
Marcus turned back to the valley. The massacre was intensifying. The disciplined Roman lines were breaking under the onslaught of the green fire. Men who had conquered the world were being slaughtered like cattle in a pen.
General Varus, the man who had sneered at Marcus only hours ago, came riding up the slope. He had lost his helmet. His cloak was scorched. He was flanked by a handful of terrified bodyguards.
He didn't carry a flag of truce. He carried only panic.
"Caesar!" Varus screamed, reigning in his terrified horse before the closed gates. "Open the gates! In the name of the gods, let us in! They are slaughtering us!"
Marcus looked down at the traitor general. "Why should I?" he called out, his voice cold. "You came here to kill me."
"They are killing everyone!" Varus pleaded, pointing back at the green hell behind him. "My men are dying! My son is in there with you! Please!"
It was the ultimate dilemma. Let forty thousand traitors die and risk the Alchemists turning their chemical weapons on the fort next? Or let them in, saving their lives, but inviting a massive, hostile army inside his walls?
Marcus looked at the green fire consuming the valley. He looked at the terrified faces of his own men. He realized the brutal truth: against this new enemy, swords didn't matter. Bodies mattered. He needed meat to throw into the grinder.
"Open the gates," Marcus commanded.
Titus looked at him, shocked. "Caesar, there are thousands of them!"
"Open them!" Marcus roared. "But disarm them! Any man who enters keeps his life, but loses his sword. Any man who fights dies!"
The order went out. The heavy timber gates swung wide.
A stampede of terrified legionaries poured into the fort. They dropped their gladii, their pilums, their shields in a clattering pile at the entrance, stripping themselves of their honor just to survive the night. They were no longer the proud Fourth Legion. They were refugees.
But as the flood of bodies pressed through the gate, Marcus saw something that made his blood freeze.
Mixed in with the fleeing soldiers, moving with a strange, fluid grace, were shadows. Figures clad in heavy, wax-treated leather coats. They wore terrifying, beaked masks that made them look like giant, flightless birds.
On their backs were brass tanks. In their hands were long, nozzle-tipped tubes.
The Alchemists weren't just chasing the traitors. They were following them in.
The Trojan Horse had just been invited to dinner.