The Heroine is My Stepsister, and I'm her Final Boss-Chapter 152 - 153: Plague?

The wind rolled like a slow wave across the field, carrying the distant clatter of armor and the sharp tang of iron. A hundred thousand soldiers stretched across the valley—standard-bearers from the noble houses, banners fluttering like tongues of fire in the afternoon light. They stood in proud formation, polished armor gleaming beneath the overcast sky, unaware that they were already walking corpses.

Henry stood beside Aurora at the overlook, the wind ruffling his cloak. From this height, the soldiers below looked like silver ants marching toward a battle none of them could understand.

He swallowed, eyes narrowing. "This is the culmination of everything we’ve worked for," he said softly. "All the noble houses, unified. Ready."

Aurora said nothing at first. Her eyes scanned the army, sharp and unreadable, her hands folded behind her back. The glow of a rune-stone flickered at her wrist—a silent heartbeat.

"They’re going to die, Henry."

Henry turned to her, his brows drawing tight. "They know the risks. This is war."

"No," Aurora said, her voice flat. "You misunderstand."

She reached into her coat and drew out a thin crystal slate, no larger than her palm. She activated it with a brush of mana. A flickering illusion lit up in the air between them—red, pulsing scans of a human body.

"Irene," she said. "Prime No. 18."

Henry frowned. "She survived?"

Aurora didn’t answer. She pointed to the scan. "This is her heart—look closer."

Henry squinted, then leaned in. Nestled beneath the ribs, almost hidden beneath a layer of muscle and artificial tissue, was a dark, crystalline core. At first, it looked like a tumor, but as the scan rotated, it pulsed. Faintly. Irregularly. And dangerously alive.

"...That’s a core," Henry muttered. "But... it’s not imperial. It’s—"

"...Fairy," Aurora finished for him, her voice like a knife. "An unstable, artificial fusion. One that has no right existing inside a human body."

He stepped back as if the image burned him.

"No," he whispered. "That can’t be. The LAW forbade experiments on fairies. It’s a death sentence. Even demons fear—"

"I know." Her tone cracked like glass. "Fairy cores are volatile. Sentient. Once exposed, they spread corruption like a disease. One wrong pulse of mana and a person doesn’t just die—they unmake."

Henry felt something cold spread in his chest.

"Then... why? Who would approve this? Who even has access to fairy relics anymore?"

Aurora turned to him, her eyes colder than the wind. "I fear It’s not the Empire....."

She let that sit.

"It’s because of that ’fucking lunatic mage’ we all know and love."

Silence dropped like an anvil.

Henry’s face paled. His lips parted, but the words didn’t come. He didn’t need to ask who she meant.

There was only one person in the Empire insane enough, brilliant enough, and reckless enough to fuse forbidden magic with military bio-engineering.

The Lunatic Mage.

Dr. Halsten Vale.

The man who once claimed souls were "merely cages with doors waiting to be opened."

Henry ran a hand through his hair. "That bastard was exiled."

"Exile means nothing when half the military uses his notes," Aurora said. "Do you really think Kury, Claire, Atlas, all of them ended up in this war by coincidence? Do you think the Primes were built without him?"

She stepped closer to the projection, voice lowering.

"He embedded the fairy cores so deep, I couldn’t even ’feel’ them. Me. And if I couldn’t feel it—what chance do these soldiers have?"

The illusion of Irene’s body flickered again. The core pulsed—ta-thump... ta-thump... ta-

It went dark.

Henry closed his eyes. "How many?"

"I don’t know," she said. "But if Irene had one, there could be others. Not all Primes were made equally. Some were built as weapons. Others as bait."

She tapped the rune-stone on her wrist, and the illusion vanished in a blink.

Henry stared back down at the army.

They looked ready.

How could they not be? Steel. Honor. Legacy. Pride. House banners flying high above elite cavalry and hardened mages. But now it all felt hollow—like watching lions walk into fire.

"I thought I was leading lions," he said. "But they’re lambs, aren’t they? Slaughter in waiting."

Aurora said nothing.

For a moment, neither of them spoke.

The wind picked up, pushing the scent of distant battlefields toward them—sulfur, smoke, blood. Henry’s mind slipped to a flash of memory—his sister Lara as a child, training with a wooden sword, refusing to cry after a broken wrist.

"You said pain was a warning," she told him once. "But maybe it’s also a compass."

He’d laughed then. He didn’t now.

"...Why didn’t you say something earlier?" he asked.

Aurora looked away. "Because I didn’t know."

"And now?"

"Now I know enough to be afraid...."

She looked at the horizon again, where the army stretched toward the cloud-covered edge of the world. Her breath caught in her throat.

"They won’t see it coming," she murmured. "When those cores trigger, they won’t go out like soldiers. They’ll go out like... like ruptured spells. Souls fractured mid-cast. The fairy core doesn’t just kill. It literally rewrites."

Henry’s jaw clenched. "So what do we do?"

"Warn the rest? Pull back?" She shook her head. "Too late. The moment Irene was fielded, the countdown began. The empire has already unleashed the primes on your kingdom,mmana net is already compromised."

A pause.

"And if it’s him, if it’s Vale—then it’s not just war we’re fighting anymore."

Henry turned, eyes narrowing. "Then what is it?"

She looked at him.

"It’s extinction...that’s why I wanted to kill that cunt, but you stopped me back then..."

A long silence passed.

Down in the valley, a horn sounded. Not in alarm. A signal of readiness. A thousand voices began chanting house mottos. A sea of belief. Of ignorance.

Henry took a step back. Then another. His hand rested on the hilt of his blade, as if grounding himself.

Aurora remained still, the wind teasing the ends of her dark hair.

He glanced back at her.

"If they die," he said, "will it be in vain?"

Aurora hesitated.

"No," she whispered. "But it won’t be noble either." fɾēewebnσveℓ.com

A shiver rippled through the sky then, like the horizon itself had blinked. The clouds darkened subtly, pulsing once with an unnatural flicker of light—mana-tainted.

Aurora noticed it.

So did Henry.

It was beginning.

And far below, in the deepest part of the camp, a soldier clutched his chest.

Unseen.

Unnoticed.

A sharp stab of pain beneath his ribs.

His heart began to pulse in strange rhythms.

A core waking up.

Just one. For now.

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