(Prologue: "The Fire That Chose Me")
The rain wouldn't stop.
Tokyo's neon signs blurred in the storm as people rushed for cover, their umbrellas bobbing like dark flowers across the Shibuya crosswalk. Among them, one boy ran without an umbrella, soaked to the bone, his school bag bouncing against his back.
Fujimaru Ritsuka, 17 years old. Average grades. Kind of awkward. The kind of guy people forget after one conversation once his use is over.
He wasn't anyone special.
Or so he thought until.
---
It started on a evening like this.
He was walking home after cram school, mind tired, heart heavy from another day of trying to "fit in."
"God!! My bad luck really loves me,huh. Like come on! How could I fall asleep for boring explanation of my Sensei in classroom, on top of that Sensei caught me red handedly and made me clean all rooms. It didn't end with that, now it's raining and I don't have umbrella at all. What did I do to deserve this Level crap?"
Ritsuka doesn't know how to feel about this day.
"Maybe I should have waited in school instead?"
Suddenly he heard vehicle sounds. That's when he heard it ... the sound of tires screeching. Glass shattering.
A car had crashed into the alley behind an old Shop. Smoke rose into the storm. No one else stopped.
But Ritsuka did.
And no one come out either but someone called ambulance and police.
His shoes splashed into the puddles as he sprinted to the scene. The car was upside down, flames licking the hood.
"Huh, I need to drag the injured person out"
Inside, the driver lay unconscious, it was a man in a long coat, blood running down his forehead. Strange metal containers were scattered across the car, glowing faintly blue and red.
"Wait!! Is he a drug dealer!! It's not important!!" Ritsuka thought and genuinely tried to help him. He can't let anyone die infront of him. He put his hands on the person body and tired to drag him out as soon as possible.
One of metal containers rolled toward Ritsuka.
A bottle.
He picked it up.
It was warm. Burning, even. Despite the rain.
A dragon emblem pulsed on its surface, flickering between blue and orange. Ritsuka's breath caught, not from fear, but from the feeling that the bottle was calling to him. Like it had been waiting.
"Get away from there!!" the driver suddenly shouted, eyes wide. "Don't touch that .... Cough...it's not meant for—!!"
But it was too late.
The moment Ritsuka held the bottle tightly in his palm, lightning cracked above the sky. A surge of heat slammed through his body, and the bottle flared with fiery light.
[ "BUILD DRIVER DETECTED."
"DRAGON! CROSS-Z DRAGON SYNC... COMPLETE."]
Something roared behind him.
A shadow moved in the flames. A creature..twisted, hunched, with clawed limbs and a mask-like face, emerged from the alley's darkness. Its body pulsed like molten glass, eyes glowing red. The driver coughed, dragging himself away.
"The Hazard… it followed me to this universe…"
Ritsuka backed up instinctively...but then the bottle pulsed again in his hand.
He didn't know why. He didn't know how. But his instincts screamed:
[Enemies Spotted]
[Emergency Protocol Activated]
{"Transform."}
The Build Driver clanked open beside the broken wreckage. Drawn by something beyond logic, Ritsuka picked it up and latched it to his waist.
{"DRAGON! ARE YOU READY?"}
{"BURNING DRAGON!!"}
Flames spiraled upward, swirling into the shape of armor.
Pain hit like fire in his bones, and then it was gone-replaced by raw power, by heat, by something primal in his chest. The armor sealed around him in streaks of fire and metal, the dragon emblem blazing across the chestplate.
His eyes glowed.
He had become something else.
A Rider.
Ritsuka didn't think.
[Auto battle mood Activated]
[Protect the host]
He moved.
His fists flew with the precision of instinct. His body dodged the monster's swings like it had trained for years. He felt every motion, every flame in his soul pushing him forward.
"This power… it's alive."
The creature screamed as he delivered a burning punch to its core. Then the driver's voice echoed again.
{"BOND BREAK FINISH!"}
Ritsuka leapt into the air, fire spiraling around his leg, and delivered a kick that tore through the rain and ignited the night sky.
The Hazard exploded into light, and the alley fell silent.
When he looked down at his hands, still shaking inside the armor, he didn't smile.
He just whispered:
"...What the hell was that…?"
Everything he is felt is real. Or did he hit his head so bad to the point he imagining things. It almost feels like TV show that he used to watch like Super Sentai.
The man in the coat staggered forward from the car, staring at him with awe and disbelief.
"You… You weren't supposed to be compatible," he rasped. "That system rejected dozens of candidates in many universes. But you—"
Before Ritsuka could answer, the man collapsed unconscious.
And so it began.
The rain kept falling.
And beneath the flickering streetlamp, Ritsuka stood alone.. the flame inside him newly lit.
The world didn't know it yet.
But its next hero had already been chosen.
Kamen Rider.
The flames hissed violently as the car erupted behind him, sending sparks and smoke into the stormy sky.
"Uncle!!"
Ritsuka still armored in the strange, burning suit rushed to the side of the man who had spoken earlier. His coat was soaked with blood now, eyes glassy, breath ragged.
"Hang in there!" Ritsuka cried, kneeling beside him. "You need help! I will take you to hospital"
The man gripped his arm, weakly but deliberately. "You… were chosen…" he gasped. His eyes seemed to look through Ritsuka, not at him. "That system… it's yours now."
"What system—?!"
"You're not ready. Not yet..." he coughed blood. "Don't waste it. Escape. Grow strong… before they find you..."
A final breath escaped his lips.
Then nothing.
'He was gone.'
Ritsuka Frist time saw someone die so close. His mind felt heavy.
Behind them, the wrecked car suddenly surged with unstable energy. Bottles those strange glowing containers shook violently inside the trunk. One by one, they ignited like fireworks.
[Deleting samples]
He heard female voice but he can't understand it's words.
Ritsuka's eyes widened. "No—!"
BOOM!
The blast knocked him off his feet. Fire swallowed the alleyway, and with it, every last trace of the bottles and the man who had spoken to him.
The only one left…
…was him.
"What the hell is going on?" He supposed to go home but he saw something else.
In the distance, he heard sirens.
Police.
He panicked. "I-I need to get out of here—!"
Without thinking, he turned and took his school bag. The suit,,,his body,...reacted instantly. His legs surged with power, and before he knew it, he was moving faster than he ever had in his life. The rain blurred into streaks as he sprinted down backstreets, his soaked school bag bouncing against him, eyes wide with adrenaline and fear.
"What is this speed...what is this body Armor…?"
By the time he reached the edge of his neighborhood, the rain was pouring harder than ever. No one saw the figure darting between rooftops and alleyways, disappearing into the dark.
When he finally stood in front of his home...his small, worn-down two story house on the hill...the armor glowed.
["System Release: Rider Form Disengaged."]
The suit dissolved in glowing blue flame, like ash in the wind.
Ritsuka collapsed to his knees in the puddles outside his door, panting.
His hands were shaking.
"Where did it go?"
He doesn't know but he wants to hide in safe place. He felt fear of unknown.
He opened the door quietly.
"Ritsuka?" came a familiar, gentle voice.
His grandfather's voice.
The old man shuffled from the living room, squinting. "That you, boy? You're drenched."
Ritsuka nodded, breath still uneven. "Y-Yeah. Just got caught in the rain…"
He lied.
His grandfather stepped closer, blinking slowly as he tried to see his grandson's face through his cloudy vision. "Come on. You'll catch a cold."
He held out a towel.
Even though he couldn't see well, he always knew when something was wrong.
"You look pale. Get some rest. We'll talk at dinner, Tomorrow is Sunday."
Ritsuka forced a shaky smile, accepting the towel. "Thanks, Grandpa…"
As he walked toward his room, every step echoed with weight. The man's final words haunted his mind.
"You were chosen… escape… grow stronger…"
He didn't know what that power was.
He didn't understand what he'd become.
But something inside him had been lit that night. A fire that wouldn't go out.
And even though his heart was pounding with fear
....he knew his life would never be normal again.
As he went into his room suddenly he heard same female voice again.
["Translating to Host language"]
["Hello, Host. Congratulations on awakening the Kamen Rider System."]
"What the hell?"
Ritsuka stared at the floating blue screen, his brow furrowed in confusion. "Kamen Rider System?" he murmured, the unfamiliar term sounding strange on his tongue. He couldn't believe what he was seeing.
["I am the system, here to assist you, Host," ]the screen replied in a robotic tone.
"Demon god!" Ritsuka panicked as he saw the system talked to him.
Was he possessed by demon?
["I'm afraid I don't have any information to answer about Demon God, If you are thinking I'm Demon God then the Answer is No. I am the system, here to assist you, Host ,"] the system responded flatly
---
Note: how is the prologue? I don't know which kamen rider I should choose for Ritsuka Fujimaru so I took all of them into system. This story happened before Ritsuka goes to Chaldea. This is Superhero type origin story at start like Spiderman but it will follow Fgo. Also I'm planning to change few Singularities to kamen rider characters and story. Just tell me how the chapter is?