The Heroine is My Stepsister, and I'm her Final Boss-Chapter 173 - 174: Eli….

The fire wasn’t hot—it was divine. It was heat born of vengeance and precision, forged in the crucible of Atlas’s rage and stitched with every drop of mana he had hoarded since the hour he stepped into the enemy’s den. The spell scroll, ancient and inscribed with forbidden runes, pulsed like a living organ in his grip. And he fed it—fed it until it swelled, until the parchment itself began to tear at the seams, unable to contain the storm packed within.

The sky did not light up—it was devoured.

The eruption was not yellow but gold-white, a holy blasphemy carved into the world by mortal hands. It wasn’t an explosion—it was a revelation. The camp didn’t burn—it ceased. Metal turned to light. Flesh to mist. Stone to shadow. Dragons mid-flight were vaporized mid-roar, wings turned to smoke before they hit the ground. Airships crumpled like paper, their mana cores bursting into molten rivers as they collapsed inward like dying stars.

The shockwave came next—a howling wall of pressure that screamed like the voice of a betrayed god. It cracked the dry hills in every direction, snapping trees and lifting debris into the heavens like offerings to some wrathful deity.

The ground howled. The atmosphere split.

Everything remembered what fear felt like.

Even the sky turned away.

The firestorm spread in all directions, double—triple—the radius Claire’s blast had covered. And hers had been legendary. This... this was scripture. The kind of fire spoken about in prophecies. The kind of light that left behind no shadows because there was nothing left to cast them.

Soldiers didn’t scream. They disintegrated.

Dragons didn’t flee. They vanished.

The Prime encampment, its thousands of elite warriors, its steel machines, its floating towers and watchfires, ceased to be.

And in the center of the annihilation’s wake stood the source.

Atlas Von Roxweld.

His golden eyes glowing through the ashstorm. His black hair whipped back by the dying winds of his own destruction. His cloak half-torn, one arm still wrapped around the half-conscious healer. His other hand—burned and raw—still smoking from the scroll’s final burst.

He didn’t smile. He didn’t gloat.

He simply breathed. And the world around him wept.

{{{......}}}

Claire blinked, her vision blurred, only to find herself slung over Atlas’s shoulder, miles from the blast. His arms were blackened, veins glowing dimly like molten rivers beneath skin. The scent of scorched mana and burning iron clung to him like a funeral shroud. He’d moved faster than light, the healer draped over his other arm, his legs a blur of mana-driven speed. He set them down on scorched grass, collapsing as his legs gave out, muscles scorched, bones cracked to splinters. His skin smoked, his breath ragged, blood pooling beneath him.

The mushroom cloud loomed on the horizon, a monument to his madness, the imperial camp erased.

[Healing mitigated... process... 36%] "Fuck," Atlas rasped, his voice a cracked blade. "Was 48% last time... fell again."

Claire retched, wiping her mouth, her green eyes wide with shock. Her limbs trembled from the heatwave, her eardrums still ringing from the pressure blast. The earth beneath her felt bruised, shivering, as if the world itself remembered the agony. "Did we win?" she asked, her voice trembling, her burned clothes clinging to her skin.

"I always win," Atlas said, his grin jagged, blood crusted on his lips.

He coughed, something black spattering the grass. His lungs tasted of rust and smoke, but he refused to let it show. Not to her. Not now. His victory had to mean something.

"We, you arrogant fuck," Claire snapped, her rage a tea kettle screaming. Her voice cracked. "My vault took a hit—forty million gold for your suicide stunt!"

Atlas’s laugh was raw, guttural, shaking the air. His body shuddered as he forced it out. "A hit? You call forty million a dent?"

His golden eyes glinted, mocking her wealth, her fury, the world.

Claire’s hand twitched. A microsecond from slapping him. Instead, she closed her fingers around the feeling and swallowed it whole.

The healer staggered to her feet, her staff glowing faintly, healing herself as her green eyes scanned the horizon. Mana was thin, strained. The air no longer welcomed spellwork—it had been devoured by the blast.

"Not again," she whispered, her voice a shiver, pointing to an army approaching, their banners fluttering in the dark.

"No," Claire muttered, her voice softening. "They’re ours."

Atlas’s smile widened, slow and sharp, like a blade remembering its edge. Behind him, the Phinixia flag unfurled with a proud crack, snapping in the scorched wind like the drumbeat of fate. Their colors burned crimson and gold against the smoke-choked sky, a symbol of promised fury that had finally arrived. Late—but perfect. Just as he had calculated.

"In time to clean the mess," Atlas muttered, his voice a low growl of triumph, the kind that vibrated from the chest of a predator standing over the corpses of giants.

No casualties on his side.

Not one.

Despite the madness. Despite the suicidal stakes. Despite the poisoned blood crawling through his veins and the Yggdrasil clawing at his heart—his reckless, brutal, plan had worked.

The crater still smoked behind him. The smell of ash and molten steel clung to the air like incense in a temple of ruin. Imperial banners lay in tatters beneath broken towers. And all around him, silence—raw, unbelieving silence—stretched across the battlefield.

Atlas took a breath and raised his head.

This was his moment.

Not stolen. Not inherited.

Claimed.

And somewhere behind him, Claire exhaled with a laugh that sounded more like awe.

His head dropped back for a moment, hitting the blackened soil. It sizzled where his skin met earth, but he didn’t flinch.

This was the cost, he thought. To change fate, you must burn in it.

The healer’s gaze shifted, her staff trembling. "Then....What about them?" she said, pointing to the sky.

Atlas suddenly felt it—a gaze like a blade, slicing down his spine, cold and lethal. His Truth Eyes flared red, catching the hum of airships, their mana engines roaring, a fleet larger than the one he’d burned.

"Motherfucker," Claire hissed, her voice dripping with exasperation. "How many of those do they have?"

But Atlas looked deeper, beyond the airships, to the source of that gaze. A shadow in the sky, a presence that made the fairy core dust tremble.

A hum pulsed inside his bones.

"Eli," he whispered, his voice low, his golden eyes narrowing