On the second floor, standing before the mirror, Nobi turned to Nobita and said:
"Character determines destiny. The people in this world and in mine have the same intelligence, but our different personalities make us act differently."
Nobita from this world blinked in confusion. "What are you trying to say?"
Nobi sighed, his tone a little helpless. "We have the same brain, so why can I do things so easily while you struggle? Think about it carefully."
Nobita's mind wasn't dull. In fact, he was just an ordinary boy. He wasn't stupid—just hopeless at studying.
In Doraemon's original stories, this had appeared more than once: whenever Doraemon pulled out a secret gadget, Nobita could instantly come up with some money-making plan. That showed he had a sharp business sense, especially considering he was only a fifth-grader!
"If anything interesting happens in the future, make sure to call me."
With that, Nobi patted the other Nobita's shoulder with a meaningful look, then stepped into the mirror.
The Opposite World
Nobi returned to his familiar room. He turned around just in time to see the mirror—his gateway to the other world—fade away. From inside his jacket, he pulled out a replica of the four-dimensional pocket and began testing the secret gadgets inside. They all worked perfectly.
He gazed out the window, his eyes piercing through the sky as if he could see not only the world, but the entire universe—the entire multiverse.
A grin spread across his face. "From here on out, the stage belongs to me!"
Previously, Nobi had obtained four secret gadgets: a four-dimensional pocket, a telephone booth, an invention machine, and a strange flashlight.
"What's this flashlight for?" he wondered.
He pointed it at a pencil, pressed the switch, and a golden light engulfed it. The pencil transformed into an exquisitely refined version of itself.
He raised his eyebrows, tested it a few more times, and discovered that anything struck by the beam would become luxurious, upgraded to its finest possible version.
"So that's it… it's a Luxury Lamp."
A toy plane could become a detailed scale model. A junky old car could turn into a Bugatti Veyron.
His thoughts raced. Could this lamp make secret gadgets themselves more advanced?
In the original Doraemon, when the lamp was used on Doraemon himself, he turned into a golden version, with the bell on his neck becoming a massive diamond.
Testing that idea, Nobi shone the lamp on his four-dimensional pocket. At first it seemed unchanged—but the moment he put it on, he noticed the difference.
Previously, he had to reach in and rummage around for gadgets. Now, his thoughts were synced with the pocket. He only had to imagine what he wanted, and it would appear instantly.
"It really did get an upgrade."
Pleased, he then turned the lamp on the invention machine and the telephone booth. Their appearances became sleeker, more refined—clearly more powerful.
After returning the lamp and booth to his pocket, Nobi sat cross-legged in front of the invention machine, lost in thought.
What is invention, really?
The encyclopedia defined it as applying natural laws to solve problems and create new solutions. But this invention machine was no ordinary tool. It contained the accumulated wisdom of the 22nd century—time technology, space technology, causal manipulation… super-science that humans of today could only dream about.
In normal human history, such technology wouldn't appear for centuries, if ever. But this was the Doraemon world, where anything was possible.
So the question was: what should he do with it?
With gadgets like these, becoming the world's richest or most famous person would be trivial. Yet when he thought about it, such goals suddenly felt dull.
"When someone can do everything… they lose the will to do anything."
He sighed. Perhaps laziness was the "backdoor" God had left in mankind, to keep humans from surpassing Him.
But Nobi wasn't a god, nor a great man.
"So… let's just make something fun."
And after much thought, his decision was clear:
A belt.
A Kamen Rider transformation belt.
Because nothing was cooler than transforming.
But which one?
The Showa-era belts were too plain. The newer Heisei belts were flashy but lacked style. The early Heisei ones? Now those were good.
Super ancient powers? The force of light? The mirror world?
He smirked. "Those idealistic belts are for girls. Real men choose high-tech!"
His eyes gleamed. "I'll make the Faiz Driver from Kamen Rider 555!"
Why Faiz?
Because it was stylish. Strength is temporary, but style lasts forever.
The invention machine's screen lit up, then displayed a chibi girl holding a sign:
[Insufficient data. Unable to model.]
Nobi froze. Of course—this world had no Kamen Rider. No Showa Riders, no Heisei Riders. The only "masked heroes" here were things like Moonlight Mask or Lion Mask.
Even with 22nd-century tech, the machine couldn't build something it had no record of.
"Can you use my memories as data?" he asked.
Normally, the invention machine lacked that ability. But this was the upgraded version. A suction-cup-like interface popped out from its side.
The chibi girl on-screen demonstrated: just press it to your forehead.
Nobi did so without hesitation. The machine read his memories instantly, too fast for him to react.
"Amazing… truly 22nd-century technology."
The chibi girl blushed shyly.
Nobi grinned. "Now, make the Faiz belt. Cancel all restrictions—anyone should be able to wear it."
[Modeling complete. Please select—][Assembled Edition] | [Complete Edition]
Curious, he asked the difference. The chibi explained:
The Assembled Edition came in parts, like a Gundam model.
The Complete Edition manufactured everything from raw materials upward.
"I'll take the assembled version."
Moments later, the machine produced a parts box, a toolbox, and a thick instruction manual.
Seeing the manual—thicker than a school textbook—he felt relieved at his choice.
The belt had countless components, and he wasn't skilled with tools. It took him until dinnertime just to assemble the Faiz Phone.
"Nobita, come down for dinner!" his mother's voice rang out.
This world's Nobi Tamako was gentle yet terrifying when angry—a classic "black-bellied" mom.
"Coming!" Nobi shouted, though he kept working.
After finishing the Faiz Phone, his hands grew more practiced. The rest of the belt came together much faster. By evening, the main body was complete.
The gloves, weapons, and accessories could wait. What mattered was testing the transformation.
Taking a deep breath, Nobi strapped the Faiz Driver around his waist, opened the Faiz Phone, pressed "5" three times, and then the Enter key.
"Standing by."
The cold electronic voice sent a thrill down his spine. His scalp tingled with excitement.
"Henshin!"
He shouted the word and was just about to insert the phone into the belt—when a chillingly magnetic voice cut through the air.
"Nobita…"
His hand froze. Slowly, with the stiffness of a broken machine, he turned his head.
At the doorway stood his mother, Nobi Tamako. A dark aura loomed behind her, her expression as gloomy as a storm.
"M-Mother…" he stammered.
"I told you to eat. And here you are, playing with toys?" she said coldly, eyes narrowing at the belt and phone. "This toy doesn't look cheap. When did you buy it?"
"I—I didn't buy it! I made it!" Nobi stuttered, waving his hands.
"You made it?" Tamako raised an eyebrow, then pointed at the stairs. "Dinner. Now."
"Yes, ma'am!" He tore off the belt and bolted downstairs.
Left alone, Tamako sighed at the mess of tools scattered across the room. "This boy… always making a mess."
But then her eyes landed on the belt and phone. She picked them up, looked around to make sure no one was watching, and grinned mischievously.
"Hehe… still fits me just fine." She strapped the belt on like a girl playing dress-up.
Opening the phone, she recalled what she'd overheard earlier: press "5" three times, then…
"Standing by."
"Hen~shin!"