Chapter Text
What if…? What if the Fastest Creature Alive met the Star?
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The world known as Earth was very different from this world that resembles that world.
This world, old, had grown in a way unlike anything that would be expected. A world formed by humans and other non-human beings scattered throughout the world. A distinct place, a gigantic world, an existence of diverse cultures and kinds, showing differentiation, as well as equality to a certain extent.
A place that is ancient and full of stories that few would ever know.
How would some know them?
Stories that became myths and legends, those myths and legends stretched across the world. Some that could even be forgotten in present days if you did not seek out those stories. Ancient stories, so fantastical and incredible, that some would be surprised at the mere mention that perhaps such things were real.
Imagine telling someone the stories, myths, legends. Everything about the world to someone.
How would people believe such things?
How would anyone have the ability to tell such a subject to someone?
No one would know how to truly tell this story to anyone. And not for lack of interest, but for lack of information about truly everything one would like to say. In this moment it would be very difficult to truly tell everything.
However, there were some stories that could be told in the Modern Era of the World.
Which of them could someone tell? Which of them would someone choose?
How about…?
The Fastest Creature Alive?!
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In this world, in space, you would see something astonishing.
Ships. Not just common ships, but extremely advanced ships. Ships of the highest cutting-edge technology! Of course they would be, right? After all, all these ships, as well as those who traveled through them, the various machines equipped with the most powerful weapons that the genius creator of these ships and machines could create! Or at least, within their limited capacity, by the fools who refused to have the decent — common — sense to give him everything he needed for his growth!
But not only those ships. No — if you looked beyond them, you would see the greatest and grand invention of this brilliant scientist. A great gigantic spherical machine molded in his own likeness! Why? Because such a thing should mirror part of the greatness of this brilliant genius not recognized by the paltry and archaic mind of those who exist in this world!
Now, you must be asking yourselves: Who is the genius behind so many marvelous and incredible inventions?
Obviously it could not be anyone else. The Great Genius, the Most Intelligent Man that Exists in the Universe, Ivo Robotnik, also known as Dr. Eggman. A man tall — very tall — with a round appearance, truly resembling an egg to a certain extent, with a characteristic mustache and dark glasses on his face. With a wide smile on his face. He watched through one of the windows of his brilliant invention — his Death Egg.
Observing the world that should be in the palm of his hand. Obviously, in his hands, this world would be advanced and he could finally elevate his constructions to go across the universe to show his grandeur. Besides finally fulfilling his greatest desire: To build his Eggman Land, his own theme park.
At his side, on each side, were two other figures. His loyal robots built by him.
[Eggman: Orbot! Cubot!]
[Orbot/Cubot: YES, DOCTOR!]
[Eggman: People say knowledge is power. Even the most idiotic understand that. And it is true! But then… why don’t those fools understand my greatness and obey my commands?!]
[Orbot: Maybe because you’re not gentle?]
[Cubot: Maybe because it’s hard to work for you?]
[Eggman: No. No, it’s nothing like that. It is simply that they are too foolish to understand the magnificence of my superior intellect that is centuries ahead of everyone in this little world!]
Counter-arguing the sarcastic comment from Orbot and the idiotic lines from Cubot, he answered while reassuming his posture.
He simply continued to look through his enormous pane of glass to look at the planet from a distance — the world he wanted and would rule in the future!
[Eggman: I think many of the problems for them not attending to my wishes have some reasons. ——First, as I said: The ignorance of those fools in obeying my commands. All because of foolishness, ignorance, and being stupid enough to believe it would be better to have a more… compassionate… leader instead of a genius with logical thinking and ahead of time like me. A genius denigrated by the sheer inability of them accepting me as the most brilliant ruler of the world to be at the top of the world!]
Speaking the words with “sadness” over the fact that people do not accept him as the supreme ruler of the world due to his intelligence and unquestionable leadership capacity — as he would declare it, though he could defend the first part, the second would be extremely questionable to a certain extent.
[Eggman: And the second reason would be… THAT DAMN HEDGEHOG!!!]
Shouting, he slammed his fist on the panel while looking through screens that appeared to show what was happening inside his Death Egg.
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A blue flash cut through the metallic corridor.
The sound — VWHOOOSH! — came before any camera could focus. The internal turbines of the Death Egg vibrated with the displacement of air, and the alarms echoed in sequence, red lights flashing while a mechanical voice sounded:
[Alert: Intruder detected! Speed… unimaginable!]
Before the robots could even turn their heads, something blue crossed the polished floor, ricocheting between the walls like a furious bolt of lightning.
The flash solidified for an instant — the figure of a blue hedgehog, a side grin, eyes sharp like blades. Running with his feet clad in red shoes and his white gloves, while easily fighting against everyone ahead of him.
Who would he be? Sonic the Hedgehog.
[Sonic: Heh. Hey, Egghead! Bet you felt my grand entrance!]
The words were almost swallowed by the metallic roar of dozens of gates opening.
A tide of gray robots, armed with saws, cannons and propellers, flooded the corridor.
Sonic took a deep breath, cracked his knuckles, and leaned slightly forward.
[Sonic: Time to dance.]
And then — he vanished.
The floor cracked under the initial impulse.
Sonic’s body became a blur, a blue spiral spinning at growing speed, climbing the walls and exploding back to the floor like a living bullet. Robots flew in every direction — hulls being crushed, metal twisting, sparks scattering like fireworks.
Every strike was precise.
Every jump, an impossible choreography.
He moved too fast to be seen — only trails of blue energy snaking between robots and bursts of light at each impact.
A volley of missiles crossed the air. Sonic jumped, spun in the air and, with one boost, ran across the missiles themselves — stepping on them in sequence before descending in a spiral over a group of robots. The impact opened a crater in the floor, and shockwaves pushed the rest away.
[Sonic: Seriously, Eggman? I’m already bored.]
He fired again — running up a wall to the ceiling, sprinting upside-down, kicking robots mid-rotation. His green eyes glowed with excitement — the kind of energy that only came from a good challenge.
From above, he spotted the next room: a circular arena full of platforms and hundreds of enemies forming ranks.
[Sonic: Now we’re talking! The party just started!]
He jumped, dropped into free-fall and, before touching the ground, charged energy into a Spin Dash!
The explosion that followed swept the entire row of robots.
Smoke, sparks and scrap metal fell like metallic rain all around.
In seconds, silence.
Sonic stopped at the center of the chaos, brushing off a bit of imaginary dust from his fur.
[Sonic: Hmph. Not even enough to warm up.]
Without even slowing down, Sonic leaned forward — SHHHH! — and was already in motion again, a blue streak cutting through the circular arena like lightning on a closed circuit.
Freshly-spawned robots barely had time to boot their joints before being shredded by the blue hedgehog’s attacks. Sonic used the metallic pieces themselves as trampolines, ricocheting from one point to another while massive mechanical arms tried to crush him against the floor.
He only laughed — dodging with tiny tilts of the body, as if he were dancing to music only he could hear.
An auto-turret rotated and locked on target.
Sonic ran along the walls — vertical, as if gravity had been rewritten to obey him — and, upon reaching the ceiling, dove in a spiral onto the turret, destroying it in a rain of screws.
[Sonic: You’re gonna have to try a little harder than that!]
More doors dropped.
A horde of flying robots swarmed in from above, firing laser beams in crossed patterns.
Sonic leapt — body horizontal — and spun between the beams as if the air were a maze visible only to him. Upon landing on one of the aerial platforms, he launched into a Spin Dash again, arcing through the air and slicing five drones at once.
Explosions. Electric blades flying. More orange flames reflected in the shine of his eyes.
Even with a hundred, two hundred, three hundred enemies thrown at him, Sonic’s expression didn’t change — he seemed to enjoy it like a sport. To him, this wasn’t war: it was an obstacle race. He used one of the larger robots as a ramp, ran across its back, jumped off its head and launched another spinning attack that shredded an entire line as if it were paper.
The arena trembled.
The metal floor began to melt from the heat of the sparks and the friction of the clashes.
[Sonic: This “army” of Eggman’s is gonna be gone before my feet even get tired.]
He jumped again, Boosted mid-air — leaving a flaming blue trail behind — and tore through another wall of robots like a living bullet.
Nothing stopped him. Nothing touched him. Nothing even grazed him.
Sonic was literally dismantling the entire room through sheer speed and confidence.
And he still smiled.
When he landed, there wasn’t a single drop of sweat to show he had exerted himself. He looked toward one of the cameras that had been watching him from the beginning.
[Sonic: Seriously? That’s it? Oh come on, Egghead — you got nothing new?]
He asked while crossing his arms and tapping one foot on the floor, looking both impatient and mocking at all the robots and machinery he had destroyed so far.
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Eggman gritted his teeth with a rage beyond possible, to the point his face turned red, while the two robots near him worried about the explosion that could happen — something typical for the Most Intelligent Man Alive.
Behind him, between the two, a figure suddenly appeared.
A little girl who seemed to be a glitched hologram — dark with red accents. Sage, one of Eggman’s greatest creations.
[Sage: Father. He is ready for the second stage.]
[Eggman: Hm? Perfect! Good work, Sage!]
Upon hearing those words from the little girl behind him, part of his rage dissipated as he prepared for what would come next.
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Sonic kept running through the massive structure while jumping and slamming into robots, crushing them. Destroying them as easily as the first ones and all the others he had faced since the moment he had started his assault. Finishing another battalion, striking one in the head and tearing it off.
[Sonic: Seriously? I was expecting more——]
Before he could finish speaking, he was interrupted — shoved through a corridor before he could fully dodge the attack.
He was thrown into a more open area with platforms and paths.
Sonic didn’t face-plant; he spun in the air, landing with ease and agility on the floor, turning to see who had attacked him. The figure that appeared flying looked similar to him, an almost perfect copy — except it was made of metal. Metal Sonic.
[Sonic: Arf. Same toys as always? At least you upgraded something? Like louder audio?]
Both prepared for the clash.
They launched at the exact same instant — two blue blurs crossing the metallic floor in parallel.
Sparks burst from Metal Sonic’s feet with every step like blades scraping steel; Sonic left only wind and a streak of light.
The first impact came without warning: Metal veered sharply to the side and tried to grab Sonic by the arm. Titanium fingers closed — CLANG! — but Sonic twisted his body out of reach in the last microsecond, slipping like water through the machine’s claws. Metal wasted no time. He swung his arm like a piston and struck downward. Sonic raised his forearm to block — and the heavy collision slid him back several meters, sparking the ground under his feet.
Raw strength. Metal won there.
Sonic pulled a half-smile.
[Sonic: Wow. Been pumping iron, huh?]
Metal advanced without replying. A whirlwind of quick, direct, calculated punches. Sonic dodged by millimeters — head tilting, torso dipping, spine bending — all at exact speed.
When he found an opening, Sonic countered with a spinning kick — WHAM! — that hit the metal torso and pushed him back a few steps. Not much. Metal barely trembled. Metal raised his hands. His chest split open and an energy beam charged — an electric roar growing.
Sonic dashed forward before the shot, turning the move into pure sprint — and Metal ran with him.
Narrow walkways, pillars, platforms — both jumping between levels, trading blows while running like two bullets chasing each other inside a barrel.
Metal tried to crush Sonic against a side pillar — extending his hydraulic arm — THOOM! — but Sonic braked almost from nothing, his nose tip centimeters from the steel, and Metal shot past, splitting the pillar in half.
Sonic took the opening — instant Spin Dash, straight into the machine’s back. Metal was hurled forward, crashing through a beam structure and dropping to the lower level.
Sonic dropped right behind, rolling and already back in stance.
Metal rose slowly, the red glow of his eyes intensifying, as if the damage annoyed him.
He opened the booster-wings on his back — and the rising engine whine warned: he was about to raise speed to the maximum level.
Sonic clenched his fists, heels firm on the floor, grin almost excited:
[Sonic: Now we’re talking. Now it looks like it’s gonna get fun.]
And then — no countdown, no dialogue, no pause — they shot off again. This time faster. Closer. Deadlier.
Metal burst ahead and Sonic kept up, the two turning into a twin-blue filament streaking through the endless corridors of the Death Egg. Walls opened on the sides and batteries of automatic cannons emerged — firing homing projectiles in Sonic’s trail, forcing him forward as if the entire environment conspired to funnel him into a predetermined fate.
Sonic realized — but had no time to refuse the route. Metal kept the pressure.
A missile whizzed past Sonic’s head — he twisted in midair to dodge it, but Metal took advantage of the split second of imbalance to lock a grab on his shoulder. Sonic kicked off the wall, using the momentum to break the grip and free himself — landing back into a running stance. The floor beneath opened — columns of laser beams swept horizontally. Metal flew through, ignoring them; Sonic skidded, slipped between two beams, and regained his rhythm with a push off the side railing.
Dozens of spider-bots dropped from the ceiling, clinging to walls and spitting electric shots — all aimed at Sonic, completely ignoring Metal. It was an ambush designed to force him along the path the base wanted.
As they dodged the shots and twisted between platforms, Sonic and Metal kept clashing mid-jump — elbows, hooks, spinning kicks exchanged relentlessly at full speed.
Metal tried to pin Sonic against an automatic gate closing quickly ahead. Sonic leapt sideways on the edge of the wall panel, ran vertically for a few steps, and vaulted over the gate just before it shut — Metal tore through it with a shoulder charge.
The corridor widened — turning into an inclined tube with glowing rails. A swarm of flying drones descended in formation, laying down a concentrated barrage along the inner lane of the tube — precisely where Sonic would have to pass if he didn’t want to collide head-on with Metal.
Metal dove in pursuit, arms raised to strike whenever Sonic lost rhythm dodging the drones.
Sonic now ran both defending and attacking at the same time — with each dodge of fire, a punch to Metal’s face; with every twist of the tube, an elbow to unbalance the machine; with every jump to avoid crossfire, a spin scratching Metal’s chassis with sheer speed. They raced toward a funnel of automatic doors, all opening in sequence and closing behind them — like mechanical teeth swallowing the corridor. Sonic realized: the Death Egg was guiding the fight.
It was steering them toward a defined arena.
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Dr. Eggman broke into an animated smile as he watched the fight through his cameras, ready to burst with joy and laughter, seeing his plan unfold exactly as he had hoped.
[Eggman: Excellent! Let’s go, Sage! It’s time.]
[Sage: Very well.]
He walked to the center of the command room, accompanied by the duo.
The center began to descend like an elevator, with the quartet inside — Orbot almost left behind by accident. As it descended, they found themselves in a more open and ostentatious area: a giant platform in the middle of a circular chamber, with three rings spinning around a central area. After a few moments, explosions and the sounds of strikes were heard.
Then, from the left side wall through one of the opening doors: Sonic and Metal Sonic appeared.
Sonic tumbled onto the platform in ball form while Metal pursued closely, his steel armor showing a few dents.
Metal Sonic lunged at his target again. Sonic dodged and counterattacked with absolute precision. Metal, despite visible punishment, pressed on like an unstoppable blade. With each exchange, the advantage shifted: Sonic read the pattern, broke the rhythm, and dismantled Metal’s AI logic with precise strikes mid-flow. A cross punch from the hedgehog spun Metal’s head two-thirds around; a kick to his metallic hip made him skid backward scraping the floor — but he still tried to regain flight. Sonic gave no pause. He advanced with a short, surgical combo — three hits to the torso, one to the neck — and Metal staggered, his dorsal stabilizer failing.
Eggman ground his teeth, yet his smile remained.
Exactly where he wanted them.
At the moment Sonic raised his arm to deliver the finishing blow——
TCHUNK.
A deep vibration ran through the floor.
From the heart of the platform, two colossal mechanical arms shot up — each forearm the size of a truck. In a split second, they clamped down on Sonic like a steel trap, gripping his torso and arms, lifting him inches off the ground, locking him in suspension.
Sonic tried to force the arms open — nothing, not a millimeter.
Metal staggered to his feet, electrically panting, lifted his head, and looked at Eggman as if awaiting orders.
Sage lowered her eyes to a holographic panel that appeared beside her, confirming the readings.
Eggman snapped his fingers once.
The entire platform seemed to pulse — motors on the outer rings began spinning around the center, slowly at first, then picking up speed… as if a monumental charge was being built.
Eggman took a breath — the smile spread wider across his face, this time impossible to hide:
[Eggman: Checkmate.]
The place where Eggman stood decoupled and began floating toward the platform where the others were.
[Eggman: Seems I have you in my hands again, Sonic! You don’t know how satisfied I’ll be when——]
[Sonic: When you finally finish off my pathetic, pitiful, insignificant form of life… Blah, blah, blah. As if I’ve never heard that before, Eggman. Really, you could try varying your villain speeches a bit before they get too stale, you know?]
Taunting in a tone that seemed carefree, Sonic’s grin stretched wide as if he were in no danger.
It made the two robots tremble, holding back laughter, while Eggman ground his teeth but kept his smile.
[Eggman: Brave. Brave even in your tragic end. Makes it all more fun when I finally rule this world with my brilliant inventions.]
[Sonic: Brilliant? Sure. But rule the world? Eh, no. Can’t let that happen, though it’d be nice if you helped people.]
[Eggman: I will help them by ruling over them, filling the world with my inventions to bring it to a prosperous era where only I, as its ruler, can provide with my unmatched intelligence.]
[Sonic: How many times have you mentioned your “superior intelligence” in this almost one-minute conversation, huh?]
Still joking, he remained calm as the rings continued to spin.
[Sonic: Look. As fun as this is, I’ve got more important things to do, and I left a Chili Dog waiting at home, sooo…]
As if emerging from Sonic’s very body.
Crystals shot out from him and formed in front of him. The Chaos Emeralds.
All seven emeralds.
They flew and hovered around him, making the eyes of nearly everyone widen in shock, before converging on the Blue Hedgehog. In an instant: his blue fur turned gold and his eyes red, effortlessly destroying the giant mechanical hands, floating in the air.
[Sonic: Let’s finish this in a few moments, alright?]
He prepared to end everything at once.
Metal Sonic readied himself to fight the Hedgehog again.
[Eggman: Yes… Let’s end this once and for all!]
With an even larger, more sadistic grin, he glanced at Sage, who nodded and pressed a button.
The moment Super Sonic lunged at Metal Sonic to finish him, lightning shot from the rings surrounding them, striking the golden hedgehog. The lightning seemed to connect to him and the Emeralds. Something that had happened long ago, was happening again.
This time Eggman felt he could——
[Sage: Father… there’s some kind of error.]
[Eggman: HUH?!]
Sage’s words interrupted what he thought was his moment of triumph.
As multiple [ERROR] screens began appearing. Metal Sonic struck Sonic, and the lightning also passed through him. Suddenly: a massive explosion erupted at the center of the Death Egg, slowly spreading throughout the entire structure.
—[X]—
From Earth, if you looked at the night sky, you could see the Death Egg in the distance.
A terrifying sight, something gigantic created by a cruel genius.
You would see it looming. You would see it glowing. And finally, you would see it “explode” into a multicolored nebula, disappearing into space — with no one knowing where that massive base had been transported.
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I apologize if my adaptation of Sonic in this story didn’t turn out that well. I tried my best.
In this IF:
-The Death Egg was transported to the Re:Zero universe because the energy of the Chaos Emeralds was overloaded by a Mana Stone that Eggman found (without knowing it had come from Re:Zero’s world itself through a dimensional error).
-The Death Egg ended up behind the Moon of the Re:Zero world, damaged.
-They arrived in the post-Arc 4 and pre-Arc 5 timeline (about two weeks before it).
-Sonic and Metal Sonic were thrown onto the planet: Sonic ended up in the Sanctuary’s domain, while Metal Sonic fell into Sphinx’s hands, who found him semi-destroyed but still operational.
-Eggman begins trying to use the resources of the Re:Zero world to repair his machine, while at the same time hunting Sonic and attempting to recover Metal Sonic, as well as figuring out how to use the knowledge of this new world to conquer his own. He even considers allying with the Witch Cult.