The moon hovered above the battlefield, dim and pale, like a ghost watching the ruins below. The temple of Lumis lay shattered, its ancient pillars torn apart, its sacred ground soaked in ash. Kaien stood in the center, his sword still glowing faintly from the last battle. Every breath he took came with pain, but he did not fall. Not yet.
The silence was unnatural. Not the calm kind of silence that comes after peace, but the kind that hides something darker. He could still feel it—the pulse of dark energy lingering in the air, like the echo of a scream.
He looked at the cracked mirror embedded in what used to be the altar wall. Once, that mirror had reflected light across the land, purifying demons for centuries. Now it only reflected the broken image of a boy who had lost too much. His reflection seemed foreign, like someone else wearing his scars.
Then came the whisper.
"You can't save them all, Kaien."
The voice was soft, beautiful, and cold. He turned sharply, sword raised. From the shadows stepped a woman cloaked in violet light. Her hair flowed like silver fire, her eyes deep and sad.
Lyra. The Demon Queen's envoy.
He hadn't seen her since the fall of the Eastern Gate months ago. Back then, she had vanished with the last breath of the dying moon. Now, she was here, standing before him as if she had never left.
"You survived," Kaien said, his tone low but steady.
Lyra's lips curved faintly. "Survived? I was never truly alive to begin with."
Her presence bent the light around her, warping the air with quiet power. Kaien gripped his sword tighter. "If you've come to fight, then stop talking."
She tilted her head, her expression unreadable. "Fight? No, Kaien. I came to remind you."
"Remind me of what?"
"That light breaks too," she said softly.
The words hit something deep inside him. For a moment, he couldn't respond. Then the ground trembled violently beneath their feet. A crack spread across the temple floor, glowing from within.
From the rift, a faint orb began to rise, shimmering with mixed energy—half light, half darkness.
Kaien's eyes widened. "The Fragment of Lumis…"
Lyra nodded slowly. "The last one. The fragment that holds what's left of the world's balance."
"That's impossible. The Fragments were sealed after the War of Dawns."
"They were," Lyra said. "Until you broke one open."
He took a step back. "What are you talking about?"
"You, Kaien," she said, her voice trembling slightly. "When you killed Azrel, the Seal of Dawn shattered. You became part of the cycle. That light inside you—it's not just power. It's corruption. The Demon King's curse fused with your soul the moment you struck him down."
Kaien's chest tightened. He shook his head, refusing to believe it. "No. I destroyed that curse."
Lyra walked closer, her aura glowing faintly purple. "You didn't destroy it. You absorbed it."
He gritted his teeth. "Stop lying to me."
"Then look," she said, raising her hand.
The Fragment flared, reflecting Kaien's image again—but this time, it wasn't just his reflection. His eyes burned faintly red, his aura flickering between holy flame and shadow.
He stumbled back, clutching his chest as pain surged through him. His mark—the mark of the Demon Slayer—was glowing out of control, pulsing like a second heartbeat.
"You see it now," Lyra whispered. "You've been fighting yourself all along."
Before Kaien could respond, the temple trembled again. A heavy presence filled the air, thick with rage and decay. A figure rose from the broken floor—a towering demon clad in armor blacker than the void. His voice rumbled like thunder.
"Enough talk, Lyra. The boy is mine."
Kaien raised his blade, fire igniting along its edge. "Erevan," he spat. "The Lord of Shadows."
Erevan laughed, the sound deep and cruel. "Still breathing after all you've lost? Impressive. But you're no hero. Just a half-broken tool of the gods."
"Maybe," Kaien said, his voice cold, "but I'm still the one who kills you."
He launched forward. The ground exploded beneath his feet. Their swords collided, sending sparks through the night. Every strike cracked the air, each one stronger than the last.
Erevan swung his blade in wide arcs that split stone and air, but Kaien was faster, weaving between blows, channeling pure light through his strikes. The demon countered with waves of shadow, but Kaien's aura cut through them, scattering darkness into embers.
Lyra watched silently, her hands trembling. There was no joy in her eyes, only sorrow.
Kaien leapt high, spinning his sword overhead before bringing it down in a flash of holy flame. The strike tore through Erevan's guard, slicing into his side. The demon roared, his body erupting with smoke and ash.
But he didn't fall.
Instead, Erevan grabbed Kaien by the throat, lifting him effortlessly. "You think you wield light, boy? You are darkness."
Kaien's hand glowed fiercely as he grabbed Erevan's wrist. "Then I'll use the darkness to destroy you."
With one final burst of strength, Kaien slammed his blade into the demon's chest. Light burst outward in a violent wave, consuming Erevan entirely. The explosion tore through the temple, shattering every remaining wall and blasting both Kaien and Lyra backward.
When the light faded, Erevan was gone. Nothing remained of him but dust.
Kaien fell to one knee, panting heavily. The mark on his chest flickered like dying fire. The Fragment of Lumis still floated nearby, spinning slowly, leaking trails of unstable energy.
Lyra crawled closer, her eyes wide with fear. "You shouldn't have done that…"
Kaien looked up weakly. "He would've killed you."
"You don't understand," she said. "The Fragment reacts to your energy. Every time you use that light, you're feeding it. You're tearing the seal apart."
He looked at the Fragment. The glow inside it twisted between white and crimson, like two forces locked in endless war.
"Then I'll destroy it," he said.
"Don't!" she shouted, reaching out. "If you destroy it, the balance between the realms will collapse. The world will fall into chaos."
He hesitated, his sword hovering inches from the Fragment. His reflection stared back at him again—half light, half shadow.
"I can't let it exist," he whispered. "Not if it means this curse spreads."
Lyra's eyes glistened. "You'll die if you do this."
Kaien smiled faintly. "Then I'll die knowing it's finally over."
Before she could stop him, Kaien plunged his sword into the Fragment.
The world erupted.
A storm of light and shadow spiraled around him, tearing through everything. Kaien screamed, the energy ripping through his veins like fire. The mark on his chest exploded in light, and for a moment, it seemed as though both heaven and hell had merged inside him.
Lyra's scream echoed through the storm. "Kaien!"
The explosion consumed the temple entirely, and then there was only silence.
When the dust settled, the ruins were gone. The forest around the temple had turned to glass, the air humming with strange power. At the center of it all stood Kaien—barely standing, his body surrounded by faint flickers of light and shadow.
Lyra crawled to him, tears falling silently. "You're… alive."
He opened his eyes slowly. They glowed faintly red for a moment before fading to gold. "For now."
The Fragment was gone. But its energy now lived inside him. The balance had shifted.
Lyra touched his face gently. "You've done it… but at what cost?"
Kaien looked up at the moon, which had turned crimson. "The cost doesn't matter. Not yet. Not until it's finished."
He sheathed his sword, turning away from her. His shadow stretched unnaturally long across the scorched earth.
Lyra whispered, "The light is broken, Kaien."
He didn't turn back. "Then I'll fight until I fix it."
And with that, he walked into the crimson night, unaware that somewhere beyond the horizon, the Demon King's heart had begun to beat again.