Pandora's Box, which contains enough energy to destroy the Earth, has finally been opened!

The Alien lifeform Evolt controls that power…

… But the Kamen Riders stand against him!

Sekai no owari de umareta hikari ima kaze no naka

(rising up underwater rays of light beaming down, as we exit the water we see Sento holding the Rabbit Bottle. He turns to look at us as we zoom in on his eye. His red eye turns blue, then into a rainbow of colors. Scene changes to the Pandora Box as it opens)

IS Infinite Build

Kireigoto dake ja ikirenai

(We move out to the Japan skyline, a massive tower in the center of Japan as we pan up to the sky.)

Yasashisa dake ja iyasenai

(Change to a sky view as every Rider passes by with a concerned look on their face.)

Ubawareta no wa nanda ?

Kawaranai sekai de

(A pair of feet running across the ground jumps off a building, as we zoom out to see Cecilia and the IS girls along with an army attacking the Tower.)

Kikoete kita no wa nanda ?

Shukusai no uta

(Chifuyu reaches out, as she and Sento hold hands, only to change to Katsuragi as he and Sento stand off against each other.)

Everything is bright

(All of the Full Bottles light up, coloring a clear blue skyline.)

Kudakechitta yume o

(Build jumps up, as Sparking rises up behind him. Panning right, we pass Rabbit Rabbit, Tank Tank, Cross-Z, Cross-Z Charge, Akatsu, Akatsu Charge, Grease, Grease Crusher. As Rogue jumps in and kicks the screen.)

Asu no hate ni hibikase ru you ni

(Scene changes to a hidden Winged Rider flapping his wings out, flying past and taking up view is a Glowing Red Dragon Rider. View changes to upper body, their body's still shrouded but with another shadow behind both, as our view is split down the middle.)

Sekai no owari de umareta hikari

Bokura hitotsu ni

(We pass in a flyby of every character not connected to the Riders.)

Ima kaze no naka

(Change to Chifuyu Smiling at the Camera)

(Tabane stares at the screen, as red and blue light color halves of her body.)

(Namba stands with his cane as the same red and blue lights illuminates him)

(Sento stands tall, as his lights are a rainbow illuminating different shades across his body)

Construct 127: Evolt Hunts the Planet

We are Sento… IS Cafe Labs…

Sitting in my lab I pour over my note again. Inputting the numbers, I hit enter and await the simulation's conclusion. 'Get it this time! Come on!' But the screen flashes red showing the danger symbol. With a heavy sigh I look over at the Panel box, picking it up and looking at it I glance at the computer. "If I use this, I'll…" I muttered, a familiar ring tone rings behind me as I pick up the phone, seeing it's Houki.

Sento:(answers) What is it?

Houki: Sento, there's Trouble! You need to get here now!

Sento:(stands up) I'll be there right away.

Ending the call, I turn to leave only to see Chloe standing in the doorway. "Chloe…" Chloe looks at the Panel box clutched in my hand. "That will put your life in danger, right?" Chloe asks me. 'Did she manage to overhear?' "Ha, of course not." I said closing the computer screen. "I ran the proper tests." I said attempting to walk past her only for Chloe to grab me by the wrist just as I was about to pass her.

Chloe:(looks down) It's that attitude that always pissed me off…(looks at Sento) So you're prepared to die?

Sento: …

Chloe:(tearing up) For Ichika? For Touto? For Chifuyu? Why don't you value yourself more? If something happened to you, what would we do?! How would the others feel, Chifuyu! Feel?! Think of the people who are left behind! Like Ichika, Houki, Cecilia, Rin, Charlotte, Laura, Yamada, Sawa-san, Me, and Chifuyu! If I don't stop now, I'll regret it for the rest of my life!...

I looked at Chloe, her face was on the verge of bursting into tears… "It'd be so painful." Chloe said, reaching out to grab the arm of my shirt. "... I sowed the seeds of this war." I said looking at her. "Is that why you're taking responsibility?" Chloe asks, then she snatches the Panel box out of my hand. "That's just sheer selfishness!" She shouts.

Sento:(clenches fist) I'm the only one who can stop this war… I have no choice but to fight.

Chloe:(single tear runs down face) Why?(crying) Why can't I get through to you?

Sento:(pats Chloe on the head) You have… when I first met you, I thought you were just an emotionless soldier… But this past year and a half, you've grown up so much…(hugs Chloe) We both have… So… Don't worry. I'll definitely come back…

With that I grab the Panel box and walk for the stairs, leaving Chloe alone. As I reach the top of the stairs, I see the Fridge door swung open. I step out and look at the counter to see Chifuyu standing quietly next to the fridge. "So you overheard?" I asked closing the fridge door behind me. "The whole thing." She said looking down at the wood counter. "... I-" Just as I am to answer, Chifuyu puts her finger up to my lips.

Chifuyu: "Why don't you value yourself more?" I've told you that before… But… I know enough to stay out of the way…(looks down) This needs to be done… I… I get that. So… Just promise me you will come back.

Sento:(nods) I will.

Chifuyu:(steps close to Sento) Just to be sure, let me remind you why you need to come back…

In silence we come close and plant our lips together. After a moment that feels like minutes, we break away. "You'll miss out on this if you don't come back." Chifuyu said with a smile. I smile and hug her one more time. "Understood mam." I said, exiting from behind the counter I walk to the entrance and exit the building.

Downtown Area… We are Observers…

The streets are filled with chaos as Hard Guardians along with Clone Smash terrorise the streets, as the sorrounding buildings are being blown to bits and civilians are being killed. Watching this all is Ichika, quietly snapping his fingers as he watches the carnage unfold around him. He glances up at the TV screen playing Seito's declaration.

Midou:(over TV) Finally, the day Seito conquered Touto has come.(stands up) Let me declare victory again.

Evolt:(scoffs) Old fart…(looks down)... Oh, right. I don't have boobs anymore…(rubs chest) … You know, for sacks of meat that are only good for attracting males they were kinda fun to mess with…(glances behind) Ah, the main event.

Sento, Houki, and Madoka run onto the scene. All three with their belts on, Sento shakes the Full Full Bottle, Houki the World Tree, and Madoka with the Crusher. "Rabbit!" "Bloom! Life Continues ON!" "Crusher!" All three insert their transformation items into their belts. Then crank. "Are you Ready?!" "Henshin!" All three shout as the armor forms on them. "Rabbit Rabbit!" "Akatsu Yggdrasill!" "Grease Crusher!" The armor attaches onto the three, as Build flies into the air to destroy a flying Clone Smash with the Full bottle Buster.

Evolt:(turns around) Finally.(snaps and points) Gettem boys!

The Hard Guardians and Clone Smash charge past Evolt and at the Riders. Two hard guardians attack Build, while the Clone Smash and the last 4 Hard Guardians attack. Build flips the handle of the Buster into gun mode, firing a beam into a Hard Guardian causing an explosion that launches the second Guardian towards Evolt who with one chop of his hand, sliced a Hard Guardian in two. With a smirk on his face, the Evol Driver appears on Evolt's waist, as he pulls out two bottles. "Cobra! Rider System! Evolution!" Evolt cranks the belt and crosses his arms. "Are you Ready?!" "Henshin." The runner and ring close on Ichika as the Evolt armor completes.

Midou:(steps over to the window) With Touto conquered, this is the dawn of the foundation of an undefeatable new country. We will be reborn…(smiles) Into a strong and powerful country.

Akatsu:(kicks Clone Smash) Is he serious?(slashes Guardian) Feels like this is the Warring States period all over again!

Grease:(shoots Guardians) Or like Japan in World War 2.(round houses Smash) Can't believe Namba has this many screws loose!

Evolt walks towards Build. "Evol Cobra!" Then phases, moving around as Build shoots at him. Evolt closes the distance and attempts to disarm Build. Evolt swings at Build's head, but Build catches the fist. The ears on the back of Build change into a pair of claws that reach over Build's shoulders and grab Evolt. Build aims the Buster at Evolt's center and fires, launching Evolt back. The claws stretch still holding Evolt, Build swings around and flings Evolt into a pillar. Build quickly removes the Full Full Bottle and shakes it. "Build up." Build inserts the bottle in again and cranks as Blue tans arrive and fire on Evolt, pinning him. "Tank! Tank and Tank! TankTank! Yabe! Tsuee~!" Build inserts a purple Full Bottle into the Buster. "Spider!" Build takes aim. "Full Bottle Break!" Build fires wrapping Evolt in a web that pinned him against the pillar. Build removes the Spider Bottle and inserts another bottle. "Dryer!" Build takes aim and fires again. The heavy gust of air keeps Evolt pinned to the webs.

Evolt:(struggling) You've beaten Phase 1 already?(pulls one arm free) How about this then?!

Evolt inserts the Dragon Bottle into his belt. "Dragon! Rider System! Evolution!" Evolt cranks the belt, as Build readies for what comes next. "Are You Ready?!" The new armor forms as flames burst out from Evolt burning away the webs. "Evol Dragon!" Evolt rushes in again, this time switching to a Boxing style of fighting that puts Build on the back foot.

Elsewhere…

Grease jumps and grabs a flying Clone Smash and pulls it down and kicks it into another smash, knocking both to the ground. "I got this!" Akatsu charges in pulling the trigger of her blade 3 times. "Niðavellir! Niðavellir Smash!" Akatsu raises the katana over her head as energy forms into a hammerhead then slamming it into the Smash destroying them.

Grease:(turns and shoots at Guardians) Here come the last Guardians!

Akatsu:(steps over) We need to finish them quickly and help Sensei out!

Midou: This country will take on the entire world. Let's show them the true power of "Modern Japan!"

Build:(blocks Evolt's Beat Crosser) Now he's waging a war against the world?!

Evolt:(chuckles) I told ya. I was right.

Evolt grabs the pommel of the blade, pulls it and slashes Build. "Hit Pared! Smash Hit!" Build stumbles back. "There is no limit to human greed." Evolt laughs to himself pointing up at the screen with Namba proclaiming Seito's power. "Or foolishness." Build stands up to his feet. "That's not true!" Build shouts, he reaches back and pulls out the Panel Box.

Build:(holds up box) We'll put an end to this useless war!(looks at box)...

Chloe:(Flashback) Why don't you value yourself more?!

Chifuyu:(flashback) Just promise me you will come back.

Build:(clenches box) I'm sorry you two. I have to protect everyone and restore peace. Nothing is more important than that.

Build removes the Full Full Bottle and swaps it with the box. As he begins to crank his belt, the Panel Box outlines turn clear and flash rainbow colors as electricity surges though Build body as he struggles to crank his belt. "B-Build… Up!" The electricity grows until it's a torrent of lighting. Build's energy radiates like a human tesla coil and shocks Evolt. "This is…" Evolt mumbles stepping back. "Scrap Finish!" "Ragnarok Finish! Yabe~!" Akatsu and Grease drop kicks, smashing the last Hard Guardians.

Akatsu:(stands up) Looks like that was the last of them.

Grease:(looks at Akatsu) Then let's find Teach and help him with Evolt.

Akatsu:(nods) Let's go!

The two run over to see Build approaching Evolt. Evolt swings at Build only for his blade to make contact with the armor but bounce off it. "... Ora!" Build swings at Evolt, his punch sends Evolt flying into the pond next to them. As water rains down on Build. "Holy Shit…" Madoka said as her helmet folded away. "Sensei…" Houki muttered looking at the Panel box.

Akatsu:(points at Belt) Wait… What's that in his belt?!

Grease:(looks at belt) Yeah… What is that? Looks like something off Pandora's Box?

Akatsu:(looks at Build) What's going on?

Evolt lifts himself up out of the water and wipes water off the visior. "Hazard Level 6!" Evolt mutters looking at Build. "So, you've finally surpassed human limits?!" Evolt exclaims catching his breath. "What?" Grease said, looking at Build. "Surpassed Human… Limits?" Akatsu asks. Evolt nods as he steps out of the pond.

Evolt:(shakes water off hands) Well done Sento.(crosses arms) So you're another one of those foolish humans.

Build:(clenches fist) What do you mean?

Evolt:(lowers arms) Why do you think I caused this war?

The dragon visior opens as his helmet folds away. Ichika's eyes are crimson with his hair now a blue and gold. Evolt smiles as he reaches into a pocket and retrieves something from it. "So I could use you to restore my own power!" Evolt said as he pulled out the Evol Trigger. "*Gasp!* No, the Evol Trigger!" Akatsu exclaims.

Evolt:(holds up trigger) You see, for a human, there's a limit to how much of the energy in this that can be used. That's why I took advantage of the power of science.(shrugs and sighs) Humans are so slow when it comes to peace time research, but Incredibly fast in war time.(points at Build) If a war began, you'd have no choice but to strengthen the Rider System, whether you liked it or not. And with this power, you would become the Ultimate Kamen Rider.(praises sky) That's what Project Build's TRUE purpose is!

Grease:(steps back) No way…

Akatsu:(stumbles back) Everything in the last 11 years… Was all for…

Build:(clenches fist) You caused a war for That?!(starts running) What Bullshit!

Build charges Evolt and throws a punch at him. The fist comes in close when Evolts helmet flashes back on and he quickly ducks under Build's fist and punches straight into Build's chest. "SENTO!" Madoka and Akatsu both shout. "Too late!" Evolt said, digging his arm deeper into Build. "Everything went as planned!" Evolt exclaims.

Akatsu:(helmet folds on) Hold on, Sento! We're coming!

Grease:(helmet folds on) Get you're fucking arm out of him!

Evolt:(chuckles) I shall take Build, who has surpassed human limits… and become Complete!

Evolt begins to phase and become transparent, as blue energy phases a figure begins to appear. "Is that?!" Akatsu rushes over as the figure phases out of Evolts body and drops to the ground. When he is caught by Akatsu and Grease. "ICHIKA!" Akatsu and Grease shout while holding Ichika passed out in their arms.

Build:(chuckles) I was waiting for that.(cranks belt) Houki, Madoka! Get Ichika out of here now!

Evolt:(looks down at arm) …?!

Akatsu:(looks at Build) Sento?... What are you doing?!

Build:(looks at Evolt) Go on… Measure my Hazard Level.

Grease:(stands up) The hell are you doing, Sento?!

Evolt:(looks at Build) What?! 6.1… 6.1… 6.3! Impossible… It keeps going up!

A bright glowing light begins to emanate form Build, as a force of energy knocks Grese and Akatsu back with Ichika in Akatsu's arms. "What's happening?!" Akatsu shouts.

Elsewhere…

Chifuyu cuts down a Hard Guardian when she sees the light glowing in the distance growing bigger. "What's… Maya, what's going on over there?" Chifuyu looks over to Maya who checks her HUD. "Umm… Wait, that can't be right?!" Maya exclaims, Chifuyu steps over as Maya opens up her HUD for Chifuyu to see. The map shows 5 figures, one enemy signature and 4 friendlies.

Yamada:(points at dots) Three of them look to be Build, Akatsu, and Graese… Looks like they have freed Ichika somehow!(points at 4th dot) See, it's Cross-Z's signal.

Chifuyu:(points at two dots) But why is Build next to Evolt?

Yamada:(shrugs) No idea… Wait… What's happening? I'm detecting a massive build up of energy?!

Chifuyu:(looks at Maya) What?! How big are we talking about?!

Maya pulls up a keyboard and inputs in some commands. "Um…" A table of information comes up on the screen. "That can't be right! What's he doing?" Maya exclaims then looks at Chifuyu. "The energy yield I see here looks to be far past Build's armor specifications!" Maya exclaims, Chifuyu looks back at the glowing light in the distance. "What are you doing, Sento?" Chifuyu mutters, holding her hand close to her chest.

Yamada:(looking over table) If I am looking at this correctly, then… If Sento keeps this up… The Build armor is going to Explode?!

Chifuyu:(eyes widen) Maya! Stay here! I'm going!

Yamada:(looks at Chifuyu) Wait no! It's too dangerous!

Chifuyu:(launches into the air) I know! I'm stopping that moron!

Chifuyu flies straight towards the light at top speed, leaving Maya behind in the center of a battlefield.

We are Sento…

I can feel the energy flowing through my veins. It burns, but not to an excruciating point, but feels like my body is edging closer and closer to a breaking point. "Thanks to Dad's experimental data, I saw through your plan!" My helmet opens up. My hair is pure blue, but my eyes, or rather my iris, is different. The right eye is the same blue it always is, but the left eye is now a glowing rainbow just like the Panel Box was a moment before.

Build:(stares at Evolt) I pretended to fall in your trap so I could save Ichika!

Evolt:(struggles) No! Do you know what raising your Hazard Level So quickly can do!?

Build:(cranking belt) Yeah!(grabs Evolt) My suit won't be able to regulate the build up of power. Causing a Massive Overload of energy!(rainbow veins begin to creep over body) I'll perish with you!

Akatsu:(stands up) No… Stop it! Don't do this Sento!

Grease:(steps over) Sento… NO!

The Build suit begins to glow red as if it were melting off my body. Evolt tries to pull his arm out, but to no avail. Evolt continues to push back with the Evol Trigger in his left hand. "This is the END… EVOLTO~!" I shout, feeling the energy reaching the climax. Evolt's suit also begins to glow, reaching its peak. "Tch! A damn Human, deceive me?! Don't Bullshit me!" Evolt shouts trying to pry the Hazard Trigger from my belt. I simply wrap my arm around and pull him in close. "Houki… Take care of Them." I said looking back at Houki, Madoka, and Ichika. I smile. "Be happy-"

We are Observers…

A massive blast of light emanates from the two as an explosion rocks the grounds. Chifuyu watches this explosion go off. "No… SENTO!" Chifuyu speeds towards the ground and lands next to Akatsu, Grease, and Ichika. "Nee-san…" Grease mutters her helmet folding away. "Where is he?!" Chifuyu demands, Akatsu her helmet fold away as she holds Ichika close.

Chifuyu:(steps over) Ichika… Houki?(kneels down) Where is he?!

Akatsu:(tearing up) He… He detonated himself with Evolt… When he split himself off form Ichika…

Chifuyu:(steps back) No… No…(looks into smoke)... No way… Sento? Sento!

"What?!" Everyone looks over to see the smoke clear and Sento falls to the floor. "Ugh… What?" Ichika mutters while sitting up. "Where?… Sento!" Chifuyu and Ichika both rush over to Sento's body, which remarkably looks fine, say for now having pure white hair. "Hey! Sento!" Ichika shakes Sento as the others come over.

Chifuyu:(puts ear up to chest)... His heart is still breathing!(looks at Sento) Sento!

Sento:(eyes open) …

Chifuyu:(smiles) Sento!(hugs Sento) Thank god…

Ichika:(sighs) What happened?

Houki:(removes bottle) Heh, I want to know that myself…

Madoka:(removes jelly) Whatever it was, it worked. Nice job Sento!

Sento:(looks at Hair) Sigh~ Too bad his plan came to nothing.

Everyone looks at Sento, as Chifuyu and the others step back from him. Sento stands up to his feet. "That voice…" Ichika mutters, he stomps over and grabs Sento by the neck of his shirt. "Don't tell me you…!" Ichika shouts, Sento looks at Ichika, his eyes now glowing Crimson. "No!" Madoka shouts. "Evolt?!" Houki exclaims, Evolt places a hand on Ichika's shoulder and pushes him back. Ichika is flung through the air and into Houki's arms.

Chifuyu:(shuddering) It… It can't be… What have you done with Sento?!

Evolt:(reaches out and clenches hand) Heh… Nothing more than Improvising. Even though I said everything was according to plan. I'll admit some of my planning was on the rails. But now, Sento is mine.

Chifuyu:(shakes head) No… No!

Evolt reaches into Sento's chest and pulls out a red Rabbit Bottle.

The design is the same as other Evol Driver Bottles but now is red with a white rabbit symbol and a bouncing rabbit piece at the base.

Evolt examines the bottle as he retrieves his Evol Driver. "Hmm… Well, whatever." Evolt strap the belt onto his waist. "Evol Driver!" Evolt pulls out the Rider bottle and inserts both into the belt. "Rabbit! Rider System! Evolution!" Evolt cranks the belt as everyone watches on as a new runner and rings form around Evolt. "Are you Ready?!" Evolt crosses his arms.

"Henshin."

"Rabbit! Rabbit! Evol Rabbit! Pf-Ha HA HA HA HA~!"

Evolt:(looks at suit) Phase 3 Complete…

Construct 127 Complete…

Next Time! Kamen Rider Build!

Sento is now Evolt, as the stakes rise even higher…

Evolt: I'll destroy everything that's important to you.

Can Ichika, who is unable to transform, save him?

Ichika: Why can't I transform?!

Will a combined force be able to Overcome Phase 3?

Houki: We'll overcome this together… For Sento!

Ichika: Give us back Sento right now!

A new Cross-Z?

Ichika: I've got to do it! No, We have got to do this!

Construct 128: The lost Genius, and Construct 129: The Ultimate Phase.