Fate's Slave - Shadow Slave X Honkai Star Rail

The first thing Seele saw was the sky — splitting open like paper soaked in light.

The second thing was the Devil.

Her head ache as she saw the mangled corpse of one of the flaming giants through the corner of her eye, the Devil standing atop it. The creature’s body pulsed with a liquid, teal radiance, as if it had been sculpted from molten glass. It had four arms, each ending in long, luminous claws that dripped with shimmering plasma. Where its face should’ve been, there was only a furnace of light — expressionless, yet seething with something so violent that the air itself refused to hold still around it.

For a moment, the sight left Seele completely silent.

Sparkle wasn’t.

”What the hell is that thing?”

Her voice cracked between disbelief and a twisted kind of awe. She’d seen monsters before — they all had — but nothing like this. The Devil didn’t move so much as distort the world by existing in it. The ground beneath its feet melted into translucent slag. Every twitch of its claws carved trails of teal flame through the air, each one flickering like a wound in reality.

Seele swallowed hard, eyes wide, heart hammering.

The thing roared.

The sound was not a sound — it was a wave. The air convulsed, the fire bent, and Seele’s knees nearly buckled as the vibration tore through her bones. A streak of light tore through the clouds, splitting them apart like a canyon.

Sparkle grimaced and grabbed Seele’s arm, pulling her down behind a half-collapsed wall.

”Whatever that is, we’re not sticking around to find out what it wants!”

But Seele couldn’t take her eyes off it.

There was something disturbingly familiar about the way it moved. A savage grace, as if Destruction was not its nature but its language. Every motion had rhythm — the same rhythm she’d once seen in battle beside—

No. That was impossible.

The Devil bent forward, its body shuddering as if it was laughing — or choking. Then, in a blur of teal light, it turned its head toward them.

The light in its chest flared.

It had seen them.

Sparkle risked a glance over the edge of the wall. Her face went pale.

”Oh no. Oh no no no. Run. Run now.”

The Devil moved.

Not with the heavy, deliberate steps of a giant — but with the sudden, impossible acceleration of something that didn’t care about distance. It blurred, flickering forward, the world warping around it like heat haze. In one heartbeat, it crossed half the ruined valley.

The shockwave threw Seele and Sparkle off their feet.

They landed hard against the shattered glass ground, sliding. Sparkle clutched Seele’s wrist.

”Move!”

They sprinted.

Behind them, the Devil hit the earth with a sound that shattered everything. The ridge they’d just been standing on vaporized into teal mist. Shards of burning stone and plasma rained around them like a meteor shower.

Seele could hear her own heartbeat pounding in her skull, every breath scraping through her throat. The air burned. Her boots sank into what had once been dirt, now molten glass.

”Why is it... chasing us?!”

”Maybe it thinks we’re food! Maybe it just hates pretty people! I don’t know!”

Sparkle yelled, her voice high and sharp with panic.

Another roar answered her.

The Devil lunged again, ripping through the air — literally tearing holes in it. The sky fractured into thin black lines where its claws passed, the edges glowing like torn fabric catching fire. Each rift imploded after a second, sending concussive bursts of vacuum that hurled debris in every direction.

Seele looked back just in time to see a storm of floating glass shards forming around it — pieces of melted landscape orbiting like blades.

They ran toward the remnants of the Ivory City’s fleet — flying ships hovering low, spotlights cutting through the haze. Soldiers barked orders in the distance, their voices thin against the roar of plasma storms.

The Devil raised all four arms to the sky.

A pulse of teal light surged outward.

The ships detonated.

No fire. No smoke. Just obliteration.

The sound followed a heartbeat later — a deafening, metallic thunder as fragments of hull and bone fell burning through the air.

Seele froze mid-run.

Sparkle shoved her forward, her tone caught between horror and fury.

”Don’t just stand there! He — it — whatever that thing is just wiped out the whole fleet!”

The Devil’s light burned brighter now, veins of plasma crawling across its body like cracks in glass. Its outline flickered between solid and liquid, as though it was falling apart from within.

Yet it kept walking.

Step by step, it advanced through the inferno.

Every step it took made the world less real.

The ground melted into luminous fluid. The sky flickered between colors that didn’t belong in mortal sight. It wasn’t just Destruction anymore — it was erasure.

In the distance, the Sun Prince’s tremendous form was fighting against the flaming giants, molten steel clashing against flaming steel. Seele was careful to not look directly at the much smaller, yet still gargantuan figures. The eldritch beings seemed to be losing, as they were easily torn apart...

Of course, the Sun Prince did was not unscathed either, but for an immortal Saint? There was no threat of dying.

It was as if the end of the world was nigh.

Seele’s throat tightened.

”What is even going on...?”

Sparkle’s usual smile was gone. Her eyes darted around desperately, calculating a hundred impossible escape routes in a second.

The Devil stared at them for a moment, before turning to look at the earth-shattering battle between giants. Then, it looked even further beyond that.

A sound hissed into existence:

”Solvane...”

It’s voice sounded like it was between a cackle and a roar, one much too distorted and corroded to describe. A mere moment later, the creature disappeared, as if teleporting.

The two women stared at where the Devil had been with shocked expressions. The only proof of it’s existence being the mass Destruction left in its wake.

”...What the fuck was that?!”

Sparkle nervously chuckled, her head rapidly turning to make sure it wasn’t around anymore.

”Probably just a prank, yeah? Now, let’s get to that ship of ours...”