Prologue: Build's...New World?

The final battle between Kamen Rider Build and Evolt has already begun and the fate of the World of Build and the parallel Earth is at stake. But despite Build's efforts, he was outmatched by Evolt's power, even with the RabbitRabbit Form.

"Why don't you face facts already? The world would've been better off without Sento Kiryu!" Evolt, in his human form, ranted.

Sento stands up and tries to punch Evolt, but he blocks it with his own hands.

"You're the root of all this. If you haven't made the Rider System and become a Kamen Rider, this entire tragedy would've never happened!" Evolt told him. "You're nothing but a sham hero that I created!"

Evolt used his powers to push Sento away. He then transforms back into his form to settle things.

"This is the end, Sento Kiryu!" Evolt said as he prepares to use his ultimate move on Sento.

But, the attack was suddenly stopped by an unknown force.

"I can't move! What the hell is going on?!" Evolt demanded.

"What are you doing, Sento?!" A voice can be heard.

"Banjo?!" Sento seems to have recognized the voice.

"I'll handle Evolt somehow! You need to run!" Banjo's voice told him. "Hey, Sento. You wanna know what kinda face I'm making now? I'm cracking a smile."

It was at that point that Sento realized something: When he saves people, he can't help but crack a smile. And then, with the encouragement from Banjo and the rest of the Build crew, he was able to stand up and take the Dragon FullBottle that came out of Evolt after he was immobilized by Banjo.

"A hero can't just turn tail and run, after all." Sento said as he equipped his Build Driver into his waist.

He then takes the FullFull RabbitTank Bottle and sets it into Rabbit and inserts it into the Build Driver.

"Henshin!"

RABBIT RABBIT! ARE YOU READY? RABBIT RABBIT! OH NO! SO FAST!

He then attempts to attack Evolt once again, but he is completely outclassed. As the fight goes on, flashbacks involving Sento's friends began to came from his memories. Mid-fight, he switches into TankTank Form to try and take out Evolt, but even that wasn't enough. Until he went into RabbitTank Sparkling and after a long battle, Build reverted back into his default Rabbit Tank form.

"And you're back to your first form...Guess that proves me right." Evolt said.

But then, the Rabbit FullBottle began to shine, turning it's usual red color into a shiny gold color.

"You sure about that?" Sento asked.

He takes the gold Rabbit Full Bottle and inserts into the FullBottle Buster, alongside the silver Dragon Full Bottle.

RABBIT! DRAGON! JUST MATCH!

"Do you really think that attack is gonna work?!"Evolt laughed.

"I do." Build simply responded/p

Build jumps very high, evading Evolt's attack in the process before landing a slash at Evolt.

JUST MATCH BREAK!

"Because Banjo and I..." Sento said before perfoming another slash. "Are a best match."

Evolt tries to counterattack, but Build managed to hit him before he can do so, pushing him back. He tries to attack him again, but he, once again, couldn't move due to Banjo's intervention.

"Sento...you smacked me awake!" Banjo's voice told him.

"Banjo, you bastard!" Evolt ranted.

"Now, let's begin the experiment."

Sento takes out the gold Rabbit Full Bottle and the silver Dragon Full Bottle, shaking it first before inserting into the Build Driver.

RABBIT! DRAGON! ARE YOU READY?

"Build Up!" Sento shouted.

BEST MATCH!

"The rules of victory has been set!" Sento says his usual catchphrase before performing his finisher.

READY! GO! VOLTECH ATTACK!

Evolt tries to counter Build by going Fever Flow, but it was too late for him as he got hit by Build's Voltech Attack, overwhelming him in the process until he was finally destroyed for good. However, he was suddenly sucked into a tornado as the two worlds began to merge. And when it finally merged, it seems that Sento is about to enter the new world...or did he?

We then see Sento lying in what seems to be a grassy field. After a few seconds, he finally wakes up and looks around as to where he landed, which it turns out that he actually landed in a forest.

"Why am I in a forest?" Sento thought to himself.

He wandered around the forest until he finally sees a town from where he was, but to his surprise, the town looks like it comes from a medieval era of some sort, as he sees a castle and houses that looked nothing like the ones found in Japan.

"Hmm, something wrong's here...Why are the building so old? And why is there a big castle?" Sento said to himself. "Is this really the new world that I have created?"

"You there! Renais dogs! Where do you think you're going?" A voice can be heard in the distance.

"What was that?" Sento asked.

He went into where the voice came from and there he saw two people, one a man riding in a horse and another a girl with cyan hair wielding a rapier surrounded by a group of bandits.

"I've never seen these people before, but why do I have a feeling that I should help them?" Sento said.

The bandits attacked the man in a horse and the blue-haired girl, but they managed to fend off the bandits...for now.

"Princess, are you injured?" The man in a horse asked in concern.

"What? Oh, I'm fine." The princess answered.

But then, one of the bandits throw in a surprise attack and the man in a horse was hit in the process trying to protect the princess.

"Seth!" The princess called out.

"You have to run, Princess." Seth demanded.

"But...I can't just leave you here." The princess said.

"Don't worry about me. You have to go to Frelia on your own..." Seth said.

Sento, who was still observing the battle in the forest, decides to help them out.

"This isn't good, if I don't go in there, the girl will surely die." Sento said as he takes out the Build Driver.

When he picked up the Rabbit Full Bottle, he noticed that the color went back to being red.

"That's strange...The last time I used this, it was yellow..." Sento said to himself.

He then immediately picked up the Dragon Full Bottle, which also reverted back to it's original color.

"The Dragon Full Bottle as well..." Sento continued. "It doesn't matter, I have to save that girl."

He puts away the Dragon Full Bottle and immediately picked the Tank Full Bottle as he is about to transform. Meanwhile, the bandits managed to reach to where the princess was.

"Did you really think you can run away from me?" The bandit said.

"Oh no!" The princess tripped while running.

"Hehehe! Grado's gonna owe me a big buck once I take out the Renais princess." The bandit said.

"Princess!" Seth shouted as he tries to stand up.

But then, Kamen Rider Build, in his Rabbit Tank Form, came out of nowhere and kicks the bandit before he could finish off the princess for good.

"W-Who are you?!" The bandit demanded.

"Me? I'll tell you. I am Kamen Rider Build. Build, as in the act of construction in order to make things." Build introduced himself to the bandit.

"Kamen Rider..." Seth couldn't believe what he saw.

"...Build?" The princess continued.

"You might wanna stand back, princess. I'll take care of him somehow." Build told her.

Build then summons the Drill Crusher and prepares himself to fight the bandit.

"Did you really think you can take me on?!" The bandit asked.

"I can. Because the rules of victory has been set!" Build said before charging towards the bandit.

Then, the battle begins. The bandit may be powerful, but he is no match for Build's speed and was blown away by his Drill Crusher.

"H-How can this be?!" The bandit said as he tries to get up.

"Let's end this!" Build said as he inserts the Rabbit Full Bottle into the Drill Crusher.

READY! GO! VOLTECH BREAK!

Build then performs a red energy slash that totally destroyed the bandit for good. It was so good that even the princess was impressed by his skills.

"Amazing..." The princess said.

After that attack, he proceeds to revert back to being Sento Kiryu and turns his attention to the princess.

"Are you okay?" Sento asked her as he lends a hand to get her up.

"Y-Yeah, I'm fine." The princess holds his hand and managed to get up. "But Seth..."

We see Seth struggling to walk towards both Sento and the princess...

"Uh...is there any place that we can settle in? I think I might be able to help him tend his wounds." Sento asked.

"Well, Frelia is just a distance away from where we are, but I don't think Seth might make it if we go there." The princess responded.

"I see..." Sento nodded.

Sento reach to his pocket to find something that will cover Seth's wounds until he finds a handkerchief. He then used it to cover the wound in his body.

"There. That should stop it from bleeding. You be careful from now on." Sento told him.

"Thank you...for not only protecting the princess, but to save my life as well." Seth nodded.

"It was nothing. I'm just glad I was there when those guys attacked you." Sento responded.

"Would you mind telling us what brings you here, Kamen Rider Build?" The princess asked.

"Oh, don't call me that when I'm not in that form." Sento told her. "The name's Sento Kiryu."

"I'm Eirika, princess of Renais." Eirika finally introduced herself. "And this is Seth."

"So, you're really a princess...And here I thought Seth just made it up." Sento said.

"Anyway, what brings you here?" Eirika asked.

"I...don't know, actually." Sento frowned.

"Eh? What do you mean?" Eirika asked, curious about his answer.

"Where am I, anyway?" Sento asked.

"You're in the border between Renais and Frelia. Why do you ask?" Seth asked.

"Renais and Frelia? I've never heard of those two places before..." Sento thought in his mind. "I begin to think that I'm no longer in the New World..."

"Well...uh..." Sento tried to come up with an excuse. "I've never been into this place in my entire life..."

"Oh, where do you come from then?" Eirika asked.

"Great. She's now curious as to where I actually came from..." Sento said to himself. "If I say that I came from another world, they might think of me as a crazy man...What should I say?"

"Uh...I came from a...very far away region..." Sento responded to their question. "I'm hoping they'll believe me..."

At this point, Sento began to sweat, he really hopes that both Eirika and Seth will believe him that he came from another region.

"Is that so? Well, welcome to Magvel!" Eirika greeted him.

"Magvel? Is that what you call this region?" Sento asked.

"Yes. But we'll explain later." Seth told him. "Right now, we need to go to Frelia to inform King Hayden of what happened."

"Oh, right. Will you join us in our journey to Frelia, Sento?" Eirika asked.

"Sure. I wanted to explore more about this place." Sento responded.

"Great! Then let us go to Frelia!" Eirika said.

And with that, Sento joins Eirika and Seth in their journey to Frelia. Will he find the answers he's looking for? Or will he be forever stuck in the land of Magvel? Be sure to stay tuned for the next chapter.