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Death's Foresight

Summary:

Reina Natsuki is the older sister of Subaru, who was taken to the world of Re: Zero 12 years before the story's start, two years before the attack on Rem and Ram's village. Having met a beautiful platinum-haired woman who took her in, will Subaru be able to rescue his sister from the clutches of the Witch Cult? Or will his sister forever be lost as the Sin Archbishop of Pride?

Or What if Subaru had a sister who was transported 12 years before the start of the anime and became a Sin Archbishop?

Table of Contents:

Arc 1 The Sin Archbishop of Pride: 1 -11
Arc 2 Sunlight Among the Shadows: 12 - 48
Arc 3 A Gathering of Stars: 49 - 91
Arc 4 An Incomprehensible Reunion: 92 - 102
Arc 5 A Timorous Week: 103 - 128
Arc 6 Kingdom of the Future: 129 - 179
Arc 7 Alpha Cygni: 180 - 233
Arc 8 The Sunset of Banan: 234 - 265
Arc 9 The Guilty and the Judged: 266 - ??

Art Credits
Deneb Arided character design by Kismith, used with permission. Original artwork: https://archiveofourown.org/works/70815311/chapters/221138001
Prylla, Ireyne, and Pierry character designs by Alicia_Archer
All images generated using local AI pipelines based on the above designs.

Chapter 1: Torn Away From Home

Chapter Text

My little brother, Subaru Natsuki, who was five years old at most, raced toward me with something pressing on his mind. “Reina! Reina! Let’s play hide and seek!”

It fit the spot. A park sat nearby, bordered by a small forest. Not so big you could truly lose yourself, and if you just picked a direction, you’d be back in ten minutes. Perfect for kids. The parents didn’t worry—kids played in there all the time. They sat on benches, keeping half an eye on us. If someone got hurt, we’d all be banned from the woods for a while. That was the deal.

“Let’s do it,” I said.

Subaru nodded and grabbed my hand, leading me toward the other kids. I ran beside him, my legs not quite long enough. I was older, but Subaru always pulled me along. Only a year apart, and still, it felt backward. Older siblings should lead. But, as usual, he called the shots. I didn’t mind. Without him, I’d just be reading under a tree, alone.

“Alright! I brought her! Let’s play!” Subaru yelled, pumping his fist as we reached the group.

“Who’s the seeker?”

“Me, me!” Subaru jumped, raising his hand.

The others exchanged glances and nodded. “Count from thirty,” one boy said. “No hiding past the big tree in the back.”

“Got it!” We all echoed.

We always set a boundary, so no one got lost, and the game didn’t drag on. The line was an old tree, twisted and ready to fall. I’d found a hole there, hidden by leaves. It was mine, unnoticed by the others.

Subaru started counting, and we scattered. I darted straight to the tree, brushing away my cover. It wasn’t a large hole, but I fit. Tucking myself in, I waited.

***

"Five... Four... Three... Two... One." Subaru’s voice echoed through the trees, too loud for a game meant to be quiet.

Reina was always impossible to find, clever in ways he couldn’t guess. Every hiding spot she picked felt like a riddle—half-hidden, half-bold, like she wanted to win, but also wanted him to figure her out. That’s who his sister was: always just out of reach. He let his eyes drift to the woods, where everyone always hid. They thought they were being tricky, but Subaru knew better. He sprinted for the trees.

The first one he found was easy. Sitting against a trunk, a boy tried his best to stifle a laugh. Subaru jumped around the tree and grabbed him by the shoulder.

"Got you."

“Damn it!”

“One down.”

The rest were in their usual spots. Too easy. But it was Reina that always made him sweat. She never stayed in one place. Time ticked on, the search stretching longer than any game he could remember. Thirty minutes turned into forty, and his frustration grew like a knot in his chest. He sprinted to her last possible spot, the boundary tree. If she wasn’t there...

“Reina!” His voice broke, sharp with nerves as he stumbled to a halt.

The hole beneath the tree was disturbed, a mess of leaves and dirt. She had been there. He crouched, staring at the place she’d vanished from. Thirty-five minutes had passed since they started.

“Reina, I give up!” he shouted. "Come out!"

Silence. He waited, breath tight, thinking maybe she had fallen asleep. But Reina never slept. Subaru’s mind ran wild with thoughts of her wandering deeper into the woods and getting lost. He ran back to the park, desperate.

"Did anyone see her?"

Everyone shook their heads. Worry crept in like cold water, seeping through him. He ran to his parents.

"Mom, Dad! I can’t find Reina!"

Panic surged as his mother stood, her face pale. His father tried to stay calm, but Subaru saw the tremor in his hands.

They searched for over an hour, yelling her name into the fading light. By the time the police were called, the woods had grown quiet, swallowing the echoes of their voices.

***

“It’s been 20 minutes. Is he gonna give up yet?” I muttered. Subaru should’ve found the others by now. He never looked long for me. A sigh escaped as I groaned, crawling out of the hole. I squinted, straining to hear any footsteps, any sign that he was near. Nothing.

I stood up, but dizziness hit me like a wave. My hand found a tree for balance, the other clutching my head. The spinning grew worse, the ground seemed to tilt beneath my feet, and then it stopped—everything went still.

The tree was still there, but wrong. Enormous. The forest had changed, stretched taller, darker. Branches swallowed the sky above, the sunlight barely trickling through. My pulse quickened. The boundary tree, the one we always used to mark the edge, was nowhere to be seen. Panic spread like fire through my chest, and I started to run.

Branches tore at my arms as I raced forward. If I kept moving, I’d get out. Ten minutes, just like always. The woods weren’t that big. They couldn’t be.

Ten minutes passed. The trees pressed in closer, the air grew thick. I couldn’t breathe. My legs burned, but I didn’t stop. Another minute. Another. Then, out of breath, I collapsed to my knees. My chest heaved as I stared at the endless stretch of trees.

“Where am I?” My voice cracked. “I’m scared... I want to go home.” A rustling sound behind me made me jump. I twisted around, eyes darting toward the noise, but nothing moved.

I scrambled to my feet. Something was watching me—I felt it. My heart pounded in my ears as I sprinted again, running blindly. The trees seemed to stretch even taller now like they were closing in on me. The rustling grew louder. Closer. A low growl sent a cold shiver down my spine.

I turned, nearly tripping, and saw them—two glowing red eyes watching from the shadows. A beast stepped out, a dark mass of fur and teeth, too big to be a dog, too wild. It snarled, and I ran, my legs moving faster than they ever had. But it was already behind me. Its breath hot on my neck, and then—pain. It knocked me down. 

I hit the ground hard, dirt and leaves in my mouth, and rolled over, staring up at the creature. It was massive, black fur matted with dirt, and saliva dripping from its jaws. A horn jutted from its snout, and its teeth gleamed in the dim light. It crouched, ready to strike—

And then it vanished. Just like that. Gone, like it had never been there at all.

I lay there, panting, trying to make sense of what just happened. My chest hurt. My head throbbed. The forest was silent again. Too silent.

Another rustle, but different this time. Not the same sound of a predator lurking. This was softer, almost deliberate. I pushed myself up on shaky arms, my head spinning as I turned toward the noise.

A woman stepped from the trees. She moved with an eerie grace, her platinum hair glowing in the muted light. She wore nothing but a white cloth tied with a blue ribbon, her blue eyes meeting mine and holding them. There was something hypnotic about her presence, something that made my fear disappear, though I didn’t know why.

“You’re lost, aren’t you?”

Her voice was soft, almost kind, but it chilled me to my bones. So I nodded, unable to speak.

“You don’t belong here,” she said softly, stepping closer. “But I can help you.”

My voice trembled. “I—I need to find my brother. My parents... they’re worried.”

“—Love. How truly precious.” Her smile deepened, with a strange amusement, as though the very word fascinated her. “I can offer you the hope you seek. To reunite with your brother, to return to the embrace of your family... but only if you desire it.”

“Yes!” I almost shouted, desperate now. “Please, just get me out of here.”

“Very well.” She raised her hands. In one, a black book appeared, in the other, a small box, the kind used for rings. “In my right is the strength to achieve your desire. In my left is the guide to that desire. Take them.”

I reached out, hesitating for only a second before taking both. The book felt wrong, cold, and heavy. The box... it pulsed like something inside it was alive. 

“What are these?” I asked, my voice barely above a whisper.

“The book is called a Gospel. It will lead you to your brother. The box contains the power you need to make that happen.”

“What’s in it?”

“Open it,” she said, her smile growing. “Place it on your chest, and you will understand.”

I stared at the box for a long moment, my hands shaking. Slowly, I opened the lid. Inside, a mass of shadow writhed and squirmed. It looked... alive. And it was moving toward me.

I raised the box to my chest, my breath catching. The shadow leaped from the box, sinking into my skin. I gasped, clutching my chest as it burrowed deep, settling near my heart. The pain disappeared almost as quickly as it came.

When I looked up, the woman was watching, tears of joy streaming down her face. 

“Wonderful,” she whispered, clapping her hands softly. “Just wonderful.”

I staggered back, still trying to understand what had happened. “What now?” I asked, my voice distant.

“Now,” she said, her smile widening, “it’s time for your induction.”

“Induction?”

“Yes. Look around, child. We’re already at the Cathedral.”