Reborn as Eren Yeager: The Gacha System

The alarm bells didn’t ring that night. That was the part Eren would remember most clearly afterward — that the end of the ordinary world arrived in total silence, and he was the only one who heard it coming at all.

He’d been asleep, fitful and shallow the way he’d slept every night since the vision at the barn, when the flicker hit hard enough to wrench him upright, gasping, drenched in sweat despite the winter cold pressing through the shutters.

Not seconds this time. Not even the barn-vision’s few stretched heartbeats.

A full minute, maybe more — fire against a black sky, the ground shaking, a scream he recognized even distorted by distance and fear, and beneath all of it, closer than anything else in the vision, a shape moving toward the southern wall, toward the district’s edge, toward the row of houses that included his own.

Tonight. Not someday. Not soon. Tonight.

He was out of bed and pulling on boots before the vision had fully released its grip on him.

"Eren?" Carla’s voice, groggy, from the hallway. "It’s the middle of the night, what—"

"Get Dad. Now." His voice came out flat and urgent in a way that clearly frightened her more than any explanation could have. "Something’s wrong. I need you both dressed and ready to move. Please, Mom, I don’t have time to explain, just trust me."

Something in his tone must have carried the full weight of the vision, because Carla didn’t argue. She turned and ran for Grisha’s study without another word, and Eren allowed himself one bare second of relief before sprinting for the door himself.

He reached Mikasa’s window in under two minutes, snow crunching under his boots, breath tearing ragged in the freezing air, and threw a handful of gravel against the glass hard enough to risk cracking it.

She was awake and at the window before the second handful landed, alert in the particular instant way she always was, like some part of her never fully slept.

"Eren?"

"Something’s coming. Tonight. I saw it — fire, screaming, close to the southern wall." His voice cracked on the last word. "I need you to trust me completely, right now, with no time to explain further."

She didn’t hesitate. "Give me thirty seconds."

She was down and beside him in less than that, scarf already wound tight, boots half-laced, eyes sharp and focused in the moonlight. "Where?"

"I don’t know exactly. Somewhere close. I need to warn the Garrison — Hannes, anyone who’ll listen — but I don’t know how to explain how I know without sounding insane."

"Then don’t explain. Just be right." She gripped his arm, steady as ever even now. "I believe you. That’s enough for tonight. Go. I’ll help however you need."

Hannes, when they reached the small barracks post nearest the Yeager house, took one look at Eren’s face and didn’t waste time asking for details either.

"You’re serious," he said, already reaching for his gear.

"Dead serious. I don’t know how I know. I just — know. Something’s coming through, close to the southern wall, and it’s coming tonight."

Hannes studied him a long moment — searching, the way adults did when deciding whether to trust a child’s certainty over their own doubt — and then made a decision that would haunt Eren with gratitude for years afterward.

"Sound the alarm," he barked to the junior soldier beside him. "Southern district, full alert. Now. Don’t wait for confirmation, just move."

"Sir, on whose authority—"

"Mine. Move."

The bell began to ring a heartbeat later, harsh and sudden against the winter silence, and within moments the whole southern district was waking — lamps flaring in windows, doors banging open, sleepy confusion turning fast to fear as the Garrison’s warning cry rolled through the streets.

It saved, Eren would learn later, perhaps thirty lives that night, in the window of time the early alarm bought.

The Titan came over the southern wall eleven minutes later — not the towering horror of Wall Maria’s eventual fall, but a smaller, wilder thing, some anomaly that had somehow gotten close enough in the winter dark to scale a weak point in the outer defenses before anyone spotted it in the ordinary way.

It moved through the outer farms first, slow and lumbering, drawn by torchlight and noise, and Eren watched from a rooftop with Mikasa at his side as Garrison soldiers scrambled to form a defensive line between it and the fleeing residents.

"We should get back," Mikasa said, tension coiled tight in every line of her body. "Your parents—"

"They’re already moving toward the eastern gate, I saw them go." His mind raced, the fragments of Titan physiology suddenly, horribly relevant in a way he’d never expected to need so soon. "Mikasa, I know something about it. A weakness. The nape of the neck — it’s the only place that actually kills them."

"How do you—" She stopped herself, shook her head. "Later. Tell me later. What do we do with that right now?"

Below them, the defensive line was faltering, soldiers’ blades bouncing uselessly off thick hide, panic spreading through their ranks as the Titan closed the distance toward a cluster of families still struggling to flee a collapsed section of fence.

Eren’s stomach dropped. A child, no older than six, had stumbled and fallen directly in the Titan’s path, too far from any adult to reach in time.

He moved before he’d finished deciding to.

"Eren, wait—"

He was already off the roof, dropping into the alley below, sprinting toward the fallen child with a speed that belonged entirely to a year of stacked reflex draws, the world narrowing to a single point of focus the way it had in the woods with the boar, except the stakes here were immeasurably higher.

He reached the child three seconds before the Titan’s massive foot would have come down, scooping her up and rolling clear, the ground shuddering with the impact close enough to rattle his teeth.

"Eren!" Mikasa’s voice, raw with fear, closing the distance behind him.

He shoved the crying child toward a soldier who’d finally broken free of the panicked line, then turned back toward the Titan looming above him, every instinct screaming to run and every fragment of borrowed knowledge screaming louder that running wouldn’t be enough if it turned its attention his way.

It did.

The Titan’s dead, wide eyes fixed on him, and it lunged.

The flicker fired at the exact right instant — a full second of warning, sharper and clearer than any he’d had before, showing him precisely where the hand would land, precisely which direction offered the narrowest, most survivable gap.

He threw himself sideways, hard, into the churned snow, and the Titan’s hand crashed down exactly where he’d been standing a half-second before.

"Eren!"

Mikasa was there suddenly, blade in hand — a real one, snatched from a fallen soldier’s grip somewhere in the chaos — placing herself between him and the Titan’s next reaching hand with the same fearless calculation she’d shown the boar, except this time the size of the threat made his heart stop entirely.

"Mikasa, no, it’s too big, you can’t—"

"Get up." Her voice was steady even now, even with a Titan’s shadow falling over both of them. "I’m not leaving you in the snow to die a hero’s death, Eren Yeager, get up."

He scrambled upright, mind racing, the fragment’s knowledge burning bright and urgent. The nape. Only the nape. Everything else is wasted effort.

"The neck," he shouted, voice cracking with adrenaline and cold. "The nape of the neck, that’s the only place that kills it, but neither of us can reach that high—"

As if summoned by the words themselves, a grappling line shot past them, embedding in the Titan’s shoulder, and Hannes swung into view on a Garrison harness, blade already angled toward the exposed nape with the practiced precision of a man who’d apparently, somewhere in his career, learned exactly this weakness through hard experience rather than a mysterious system.

"Move!" Hannes bellowed, and the Titan’s strike came down toward them both a half-second before his blade found its mark.

Eren grabbed Mikasa and threw them both clear, the Titan’s collapsing weight crashing into the snow behind them close enough to throw ice and debris across both their backs, and then, suddenly, terribly, silence — the Titan’s body already beginning to dissolve into steam and vapor the way Eren somehow, impossibly, already knew it would.

They lay in the snow for a long moment afterward, breathing hard, ears ringing, the adrenaline slowly draining out in favor of trembling aftershock.

"You," Mikasa said finally, voice shaking despite her best effort to keep it steady, "are going to explain everything. Tonight. No more someday. No more not yet."

"I know." He turned his head to look at her, snow-dusted and fierce and utterly, gloriously alive, and felt something in his chest crack open entirely. "I promise. Tonight. All of it."

"You knew," she said, quieter now, working through the pieces even through her own shock. "You knew where it would come down. You knew the nape mattered before Hannes even said it. You’ve known things for a long time, haven’t you? Things you shouldn’t be able to know."

"Yes."

She studied him a long moment, and he braced for fear, for doubt, for the distance he’d always dreaded putting between them the moment the truth finally came out.

Instead, she reached over and took his hand, snow-cold fingers lacing through his, steady despite everything that had just happened.

"Okay," she said simply. "Tonight, then. Tell me everything. I’m not going anywhere — I already told you that, and I meant it before I knew there was this much to mean it about."

Something in his chest, tight and afraid for a year and a half now, finally, fully loosened.

"I love you," he said, the words arriving without calculation for the first time, raw and simple and entirely true. "I should have said that before tonight too. Before any of this. I love you, and I’m about to tell you something that’s going to sound impossible, and I need you to still be here when I’m done."

"I love you too." No hesitation at all, snow melting against her cheeks, blade still loose in her free hand. "I’ll still be here. I already promised you that. I don’t break promises, Eren. Especially not this one."

He pulled her close, right there in the ruined, steaming snow, the aftermath of the district’s first real brush with the horror he’d spent a year and a half preparing for, and kissed her like the world had actually almost ended and hadn’t, like every stolen moment on rooftops and porches and riverbanks had been leading toward exactly this — not the end of secrets, but the true beginning of finally facing what was coming together.

Later, once the district had settled into shocked, grateful chaos — soldiers counting survivors, Carla sobbing with relief into Eren’s shoulder, Grisha’s face pale with a fear that went deeper than the night’s danger alone — Eren sat with Mikasa on the same rooftop where it had all begun, and told her everything.

The first life. The gacha system. The fragments. The countdown ticking down toward Wall Maria’s fall, toward a fate he’d spent this entire second chance trying to outrun.

She listened without interrupting, without doubting, her hand never once leaving his through the whole impossible story, and when he finally finished, exhausted and raw and terrified of her answer, she only said, quiet and certain:

"Then we have a hundred and twenty-five days left to get ready. Together. No more secrets between us — not because I don’t trust you to carry it, but because I refuse to let you carry it alone anymore."

One hundred and twenty-five days.

For the first time since the countdown began, the number felt less like a sentence and more like a deadline he might actually meet — not because the system had given him enough power, but because the girl beside him had just proven, in fire and snow and blood, that she’d rather face the ending with him than be protected from it without him.