Tsutsumi stood motionless, calmly watching Kamen Rider Build battle one of this world's monsters.
From what he remembered, there were only two ways to gain a Rider's power, befriend them, or destroy them. The first option would be tricky, especially since he couldn't transform into a Kamen Rider.
Well… not exactly.
He pulled out a card.
Kamen Ride: Decade
It wasn't that he couldn't become Decade, it was that he knew the cost. The moment Decade appeared, all worlds would begin to merge, leading to their eventual destruction before splitting apart again into fresh new worlds. A never-ending cycle of annihilation and rebirth.
The previous Decade, Kadoya Tsukasa, had lived a relatively normal life… until he became Decade.
And Tsutsumi had inherited all of that power. Which meant that the instant he transformed, the countdown to the worlds' convergence would begin.
Sliding the card back into its holder, Tsutsumi narrowed his gaze at the Rider below. He drew another card, this one bearing Build's image, its colors dulled to lifeless gray.
"My current power isn't enough," he muttered. "I'll deal with them later." Fighting a Rider in full transformation would take more than his current strength.
Turning away, he remembered how Decade had a friend, a thief who plundered treasures from other worlds.
A faint smirk crossed his face. "Maybe I can try that too."
He pulled out another card.
Form Ride: Great Explosion Murder God Dynamight
A flash of light engulfed him, and his body shifted into the explosive form of Bakugo Katsuki.
...
Inside a coffee shop, Tsutsumi, now having Bakugo's appearance, stares at the shady uncle on the other side of the counter.
According to his memory, this guy is supposed to be the final big bad of Kamen Rider Build. But then again, that is from another world, and from the memory of someone completely different.
"Here is your coffee, sir." The shady uncle handed Tsutsumi his coffee with a polite smile before returning to his work.
After taking a sip, he nearly spat the coffee out, but, choosing to be polite while trying to understand this world, he simply placed the coffee back onto the table and decided not to finish it.
Tsutsumi sat calmly, waiting, but upon seeing nothing had changed, he decided that there wasn't anything special here for him to do.
Without saying a word, he slipped away like a ghost; if the coffee were any good, then he might actually pay for it.
Tsutsumi waited, and upon seeing the shady uncle walk out from the closed shop, he saw the shady uncle place a bottle into a gun, then to his amazement, the shady uncle transformed into a red armor figure.
Feeling a glow inside his pocket, Tsutsumi pulls out a new card that has the image of a masked figure, completely different from the one the shady uncle just turned into, but their image is grayed out.
Kamen Ride: Evol
"Interesting..." Tsutsumi murmurs to himself before the Aurora Curtain appears, taking him away.
...
Inside an apartment building, Evol sat across from a young man, the two deep in conversation, until the Aurora Curtain split the air.
Bakugo stepped through, grenade gauntlets in hand.
Neither of them had time to react. The pins clicked free.
Twin detonations tore through the building, sending fire and debris into the sky. The shockwave rattled the streets below, triggering screams and chaos as sirens wailed in the distance. Police and firefighters swarmed the scene, searching for survivors from the wreckage.
High above, Tsutsumi stood on a nearby rooftop, calmly snapping a photo of the smoking ruins. Behind him, a crowd of bewildered people whispered among themselves, former residents of the building, now inexplicably safe outside.
Before the blasts, Tsutsumi had used the Aurora Curtain to evacuate them, leaving only Evol inside. Even the young man wearing the Build Driver had been pulled to safety.
Destroying this world's Build and claiming his power might have been tempting. But his mother was still a pro hero, and the idea of killing innocents left a sour taste. If he accepted the title of Destroyer without even becoming Decade, how could he ever face her?
"Hey! What just happened?" The young man with the Build Driver, wide-eyed and breathing hard, grabbed Tsutsumi's shoulder, spinning him around. "Who are you? How did you do that?"
"And you are?" Tsutsumi's voice stayed cool, steady.
"Katsuragi Yukiaki. Researcher at the Touto Institute of Advanced Matter Physics," he replied, his gaze tightening. "So? Who are you?"
Tsutsumi's expression didn't change. "Just a passing-through Rider. Remember that."
He raised his camera and took a photo of Katsuragi.
"Rider? Are you… also a Kamen Rider?" Katsuragi's eyes narrowed, the word clearly resonating with his own tech.
"Not exactly." Tsutsumi's gaze shifted past him to the dazed civilian, people he'd pulled from the building moments before the blast. "But close enough."
He turned away, walking toward the roof's edge. "Be careful. You can't face him in just human form."
With that, Tsutsumi stepped off the ledge. Katsuragi rushed forward, heart pounding, only to find the boy gone, leaving nothing but the wind.
...
Returning to his own world, Tsutsumi set down several full bottles alongside a large backpack stuffed with stolen items from Build's world.
He picked up two bottles that formed a best match, studying them for a moment before giving them a light shake.
"Hmmm… maybe I should help Katsuragi gather all the full bottles," he murmured, a faint smirk tugging at his lips. "If I do, I might just get Build's Rider Card."
His gaze drifted toward the clock.
23:30.
The next morning, Jiro climbed through the window and yanked a bleary-eyed Tsutsumi out of bed, dragging him to school.
U.A.'s curriculum rolled on as usual, English in the morning, regular classes afterward.
It was boring.
So boring that Tsutsumi asked to use the bathroom… then vanished completely.
Hound Dog, the head of student discipline, was livid when he realized the boy was nowhere to be found. He swore he'd chew Tsutsumi up if he ever caught him. Aizawa nursed a headache, while Nezu quietly pondered how Tsutsumi had disappeared without leaving a trace.
By afternoon, Tsutsumi reappeared in class as if nothing had happened. Ida immediately stormed over, hand raised like a traffic baton.
"We aspire to become heroes! We set the example! How can you-"
The lecture droned into one ear and right out the other. Tsutsumi walked toward his seat. Ida tried to block him. Tsutsumi bumped into him, sent him sprawling to the floor… and stepped right on him like he was a doormat.
Everyone: "..."
The class went silent.
Even Bakugo wouldn't have done that.
Several eyes shifted to Jiro, who was already facepalming. No wonder the guy had no friends; finding someone who could stomach his personality was a tall order.
Tsutsumi dropped into his seat between Bakugo and Todoroki, completely unconcerned. The incident was quickly forgotten when the door rattled under the arrival of someone much larger than life.
Two great forelocks shot toward the ceiling. A blinding grin spread from ear to ear.
"I AMMMM!"
A hurricane of red, white, and yellow exploded into the room. The number one hero stood before them in his Silver Age costume, the gust from his entry still rustling papers.
The class lit up, surprised, thrilled, awestruck.
Tsutsumi wasn't impressed. Compared to the Kamen Riders he'd seen in his dreams, All Might felt… less heroic. Those Riders didn't fight for paychecks or glory. They fought because it was right.
When chaos consumed the world, they didn't run away, they walked toward it. Some lived and died poor, unsung, and forgotten, their deeds remembered only by the few who knew them.
"Coming through the door like a normal person!" All Might boomed, clearly excited to teach his first class.
"For your Foundational Hero Course, we'll be building your hero skills through various trials. You'll get credit, of course. And our first class is…"
In a blur, he produced a card marked with the word Battle in bold red letters.
"Combat Training!"
A mix of cheers, nervous gulps, and whispered chatter rippled through the class.
"A hero must know how to fight to protect others! And we can't forget-"
At the back of the room, lockers hissed open. Smoke curled out as platforms slid forward, each carrying a suitcase.
"Costumes! Clothes make the hero, as they say. Get changed and meet me at Ground Beta. Do not keep me waiting, young heroes!"
With that, he blasted out of the room, leaving a dust cloud behind.
The boys' changing room buzzed with chatter, except for the corner occupied by Tsutsumi, Bakugo, and Todoroki, whose combined "stay away from me" aura kept everyone at bay.
By the time they stepped outside, All Might was already there, ready to watch the next generation introduce themselves to the world.
As the students filed out, their hero costumes showed off their personalities, flashy, colorful, and practical.
Tsutsumi's stood out too… but not for the usual reasons. It didn't gleam with heroic flair or cutting-edge tech. Instead, it radiated the kind of presence you'd expect from someone stepping out of a villain's lair.
In the open yard, the boys couldn't help sneaking glances at the girls in costume, none more shamelessly than the purple-haired midget. The girls were subtler about it, but Tsutsumi noticed their eyes drifting toward a few of the boys as well.
"Ryo, your hero costume…" Jiro asked bluntly, "Why does it look like something a villain would wear?"
He was dressed in Kadoya Tsukasa's Dai Shocker leader attire, black leather traced with a bold magenta stripe running from his wrist to his armpit, then down his side. His collar flared wide, revealing part of his neck, layered over an open high-collared vest. On the upper back, the Decade logo blazed in magenta, with another stamped on his left leg just below the knee. Black leather pants and boots completed the look.
The only thing missing was the Dai Shocker emblem on his chest.
"Exactly," Tsutsumi replied without hesitation.
Everyone: "…"
…You're not even going to try denying it?
All Might sweatdropped. He'd known Tsutsumi was a problem child, but this was a new level. His How to Teach for Dummies book didn't cover what to do when a student proudly admitted to looking like a supervillain.
...
"Today, we're doing battle trials," All Might announced. "Each student will be paired with a partner and assigned as either the hero team or the villain team. Heroes must infiltrate the building and either capture the villains or touch the fake bomb they're guarding. Villains win by preventing this until time runs out."
He gestured to a box filled with numbered balls. "Draw a number, matching numbers will form a team."
Tsutsumi reached in, pulled a ball, and ended up partnered with… someone whose name he didn't remember, nor cared enough to.
The early matches were loud, flashy, and at least for him, mildly entertaining. Midoriya and Uraraka versus Bakugo and Ida tore through nearly half the building. Oddly, the hero team limped away victorious, while the villain team barely had a scratch. Todoroki's match ended even faster, he froze the entire building in one move.
Finally, the last match.
Team E: Aoyama Yuga & Ashido Mina.
Team F: Sato Rikido & Tsutsumi Ryoko.
"Let's get this over with," Tsutsumi muttered, glancing at Sato, the tall boy in a yellow jumpsuit standing beside the fake bomb. "Guard it. I'll handle them."
Before Sato could respond, Tsutsumi was already gone.
As Aoyama and Ashido made their approach, Ashido's acid accidentally splashed onto Aoyama's purple cape. His gasp of outrage was cut short by the sound of slow, deliberate footsteps.
Tsutsumi rounded the corner, his calm gaze locking onto the two.
From the observatory room, everyone watching thought the same thing:
He really does look like a villain.
"Let's make this quick."
Tsutsumi drew a card, raised it, and slid it into his belt.
Attack Ride: Zone
Magenta lightning flared in his eyes, casting an ominous glow. He didn't wait for speeches. He blurred forward, fist smashing into Aoyama's face. Glasses shattered, nose broke, and the blonde slammed into the wall.
"Aoyama!" Ashido shouted.
"Eyes on the enemy," Tsutsumi reminded her, spinning into a kick that slammed into her ribs and sent her tumbling.
Aoyama's belt lit up, firing a laser. Tsutsumi sidestepped, countered with a kick to his side, cracking the belt casing.
Tsutsumi realized that Aoyama's belt isn't like his; Aoyama is more of a support item for him to use his quirk.
Odd, since a quirk, whether useful or not, would at least be compatible for its owner. And could be used without harm unless it was overused.
Still, this isn't his problem.
His fist snapped up in an uppercut, snapping Aoyama's head back.
"Get away from him!" Ashido hurled a wave of acid.
Magenta lightning flared in his eyes as Tsutsumi grabbed Aoyama by the hair, dragging him forward as a human shield. The acid sizzled against his costume and skin, and he screamed. Before Ashido could even apologize, Tsutsumi flung Aoyama into her.
They crashed together. Before she could push him off, Tsutsumi stomped down on Aoyama's back, pinning him onto her.
"Surrender," Tsutsumi said coldly, "or continue."
"W-we surrender!" Ashido stammered, fear flashing in her eyes.