Reborn as an Extra with the SSS-Divine Debt System and my Past Skills

Merci stirred awake, her body heavy but no longer burning from exhaustion.

She lay still for a moment, breathing in the damp air of her makeshift cave, when a faint beeping broke the silence. Her eyes narrowed. That was no ordinary sound.

With a grimace, she forced herself upright and summoned her interface.

The familiar screen flickered into existence, and there it was—an unopened message marked with the crimson seal of her lord.

Silvanus.

Her claws trembled as she opened it. The demon king's voice filled her ears, cool and commanding, carrying with it the weight of chains she wore gladly.

[Finish what you started. The human settlement must fall. Only then will you be permitted to return. You have three days. Fail, and do not bother crawling back.]

The message ended abruptly, leaving behind only the faint echo of his disdain.

Merci lowered her head.

"As you command, my lord."

Three days. Her lips curved into a faint smile. Whether she lived or died mattered little. To serve until the end—that was her purpose.

And besides, she had already sown the seed of destruction. Hidden among the spoils Lucius had carried back from the junkyard, her gift waited. The bomb. Still pulsing. Still alive.

One way or another, the Dawn Settlement would burn.

The morning sun was gentle over the settlement, but inside, Lucius felt nothing but unease.

He moved through his routine—checking on the guards at the barrier, greeting the scouts returning from night patrols, speaking briefly with the healers.

All seemed calm, but his instincts screamed otherwise.

It wasn't until he reached the laboratories that his unease found form.

The scientists were pale, some clutching their notes as though holding them tighter might make the problem vanish. When they saw him, their shoulders slumped in relief.

"Lord Lucius! Please, you need to see this!"

One of them cried.

They led him into the center of the room, where a strange device sat on a reinforced table.

Small, spherical, faintly metallic—yet what drew his eyes was the rhythmic pulse of mana radiating from it. It beat like a second heart, heavy and dangerous.

Lucius's gaze sharpened. A Mana bomb.

He studied it silently, his expression unreadable, while the scientists kept a cautious distance. Finally, one stammered.

"We—we think it's unstable. If someone so much as touches it—"

"Step back."

Lucius ordered. His tone was calm, but the edge behind it left no room for argument.

He approached slowly, extending his senses. The mana twisted and writhed like a caged beast. Definitely not something crafted by humans. Merci's work.

Before he could do more, hurried footsteps pounded down the hall. A soldier skidded into the room, sweat dripping down his forehead.

"Lord Lucius!"

His voice shook.

"It's bad—outside the barrier! Monsters! Dozens—no, hundreds! They're attacking anything they see, ramming the shield, tearing at the walls! People are panicking—we don't know how long the defenses will hold!"

A sharp silence filled the lab. The scientists exchanged terrified glances.

Lucius straightened slowly. Two crises, layered neatly together. Bomb inside. Horde outside.

And then, the familiar static of the system echoed in his ears.

[Mission Updated: Protect the settlement. Neutralize the bomb. Survive.]

Lucius's lips curved faintly.

"So this is the next mission, is it?"

He adjusted his coat, the weight of his weapons settling against him.

"Very well. If fate insists, then I'll play along."

Outside, the roars of beasts shook the ground, rattling the settlement walls like drums of war.

Families huddled in corners, soldiers scrambled into formation, and above it all loomed the relentless pounding against the barrier.

Within the laboratory, the bomb pulsed harder, responding to the chaos outside, as though feeding on it. Each beat throbbed like a countdown.

Lucius placed a hand lightly on the table, eyes narrowing.

"Three days? No. I'll end this before nightfall."

Lucius straightened, turning to the soldier who had burst into the room.

"Gather the guards. Form squads and split them along the northern and western walls. Do not waste energy striking the beasts directly—focus on keeping the barrier intact. Buy time."

The man saluted shakily before running off.

The scientists still hovered near the door, pale and trembling. Lucius spared them only a glance.

"Secure this lab. No one touches that device until I return. If anyone so much as breathes too close, I'll know."

The weight of his words sank in; they nodded rapidly, retreating toward the far wall.

Lucius left the laboratory, the distant thunder of roars growing louder with every step.

By the time he reached the courtyard, the ground shook with each impact against the barrier. Families clung to each other, their eyes darting to him the moment he appeared.

Fear and expectation mingled in their gaze.

"Go inside. Lock the doors. Trust the guards."

Lucius told them, voice calm and steady.

Some hesitated, but his composure was iron; they obeyed, shuffling quickly back into their homes.

Across the wall, soldiers stood rigid with their spears and rifles, trying not to flinch each time a monster's claw scraped against the shimmering barrier.

Lucius walked among them, his presence enough to settle some of their shaking hands.

A scout jogged to him, breathless.

"My lord—this isn't just a stray pack. It's an organized horde. Someone's driving them toward us."

Lucius's eyes narrowed.

'Merci again.'

It fit too well. First the bomb, now this assault—layered traps meant to fracture them.

"Good. That means their puppeteer is close."

Lucius murmured.

He raised his voice, projecting it across the ranks.

"Hold the line. You don't need to kill them—only outlast them. The barrier will hold so long as your resolve does. I will deal with the root of this."

The soldiers straightened, clutching their weapons tighter. The panic in their eyes dimmed, replaced by grim determination.

Lucius turned back toward the lab. Two enemies. Two fronts. If he played this wrong, the settlement would be rubble before nightfall.

"System, keep count. I don't plan on failing this mission."

He muttered under his breath.