Asa mo yoru mo koi kogarete hoshi ni naru yo kimi mamoru tatakai wa yukue shirazu

(From the sky the camera falls down on the nation of japan and then close up to the Skywall, where the red light beams down on Chifuyu, as she reaches out. Scene changes to Sento the light going up his body, Sento brings his clenched fist close to his chest before reaching out. In the background Stalk looks on.)

ashita to kinou no kousaten de majiwaranai kimi to boku ima iku yo boku wa nagareboshi

(Sento stands with everyone looking on with a serious face. Scene changes to Chloe in tears as Sento reaches out before a Shadowy hand grabs Sento's hand. Scene changes to Build, Cross-Z, and Akats standing ready to fight.)

IS Infinite Build

sekai ga kuchihatete mo kawaru koto no nai mono ga aru

(Camera flashes to Ichika's face then Cross-Z, then to Cross-Z jumping off a building and flying into battle. Scene changes to Cecilia taking aim with her rifle and firing off a shot)

namida wo koraete demo mamorubeki mono ga bokura ni wa aru

(The shot passes Rin, who swings at the camera, Charlotte blocks incoming fire before firing back)

nanmannen nan okunen mae kara no messeji ga tainai de uzukidasu narihibiku

(Changes to Laura swinging her cannon and aiming before firing off a shot, the shot flies past Akatsu as she thrusts with her blade, under the helmet Houki let's out a tear.)

shagareta koe de asu wo yobu kizu darake no te de kimi mamoru

(Grease drops towards Cross-Z with her weapon at the ready, Cross-Z spins around and thrusts his blade at Grease, their weapons let out a shockwave of energy as the two steare each other down. Scene changes to Tajimi and Phantom Task behind her. Looming over all of them is a Mech hidden in Shadow, a beam charges up before firing at the screen.)

I continue to fight I continue to fight

(Gentoku walks forward with Yamada behind him. Camera changes to an up close look at Gentoku up close, looking at one half of Gentoku's face is with a creepy smile. Camera switches to other side to see a dulled out Gen with purple crack veins creeping up his face. Stalk Revels in everything.)

asa mo yoru mo koikogarete hoshi ni naru yo kimi mamoru tatakai wa yukue shirazu

(Sento Drives his bike before swerving to park as he looks over the ridge. Looking over a hill, Sento looks on at Hokuto's army. Stalk flies in with new armor covering her.)

ashita to kinou no kousaten de majiwaranai kimi to boku sadame wo kirisaku nagareboshi

(Camera flies past the cast in different poses looking at the camera M's face shows anger, as camera changes to Sento also with a serious face, before Chifuyu drops in besides Sento. Sento and Chifuyu reach out to each other, but a shadow creeps up Sento's hand. Sento brings his hand close to his eye, the camera focuses on his eyes to see a shadow in both eyes.)

hakanaku kiete nakunaru koto sae kowakunai

(Still focusing on the eye, appears an all black boots, hand, chest piece, then belt with a Red Trigger upon it. Then to Normal Build as his helmet folds out, the camera pans back to look down upon the entire cast. Camera changes to a Full Bottle being tossed before being paused in frame.)

Construct 71: Secret of the Unknown Bottle

Sento: War between Touto and Hokuto broke out over the Pandora Box, an artifact containing a tremendous source of energy. Kamen Rider Build, other wise known as Kiryu Sento, chose to fight to protect Touto, facing many deadly opponents such as Hokuto's Kamen Rider Grease and the Smash Trio.

Utsumi: In the end, the key to this war would be the Sclash Driver.

Sento: Um… Who are you?

Utsumi: It's Utsumi…

Sento: Oh, you're that cyborg-

Utsumi: NO! That's just a nickname you called me.

Sento: But I thought you were… Ah! Because you're a cyborg you survived!

Utsumi: NO! Sigh~ It'll all be explained in Construct 71.

We are Observer

Gen:(dumbfounded) Utsumi…

Utsumi: I suppose you're wondering…(fixes glasses) Why I'm still alive after you shot me. It was Stalk. She saved me.

Gen:(sits down) I didn't have any other choice back then.

Utsumi:(scoffs) Luckily you only damaged my shoulder. Be glad it was only that, any more and I'd take that statement as bullshit. But onto the point. I'll be your point of contact for Nanba Heavy Industries from now on.

Gen: Very well… Then tell me…(looks at Utsumi) How is Faust still operating if it was shut down for good? The Hard Smashes could not have been created without Faust's knowledge and resources… You must have created a branch of Faust in Hokuto, haven't you?

Utsumi:(sits down) I'm afraid I am unable to answer that question.(turns to window) I'm not obligated to answer or disclose such information-

Gen:(stands up) STOP FUCKING WITH ME! Faust was founded my Katsuragi and I! The remnants Faust disappeared from the prison while they were being transported. You took them to Houkuto didn't you! I won't let you have your way with this.

Utsumi:(sighs) That's… Unfortunate… Please leave.

Gen: What did you say?

Security enters the room and train their guns on Gen's head. "I only let you in here to explain the situation." Utsumi says getting up and putting a hand on the side of the window, Utsumi looks out the window. "Now if you'll excuse me. I have work to do." Utsumi says, and begrudgingly Gen storms out of the room.

Infinite Stratos Cafe… We are Sento

"Kamen Rider Grease… Her strength was real." I explain as Ichika and I are patched up. "But how is she stronger with the same belt?" Chloe asks, I sigh. "That just goes to show how much more experienced she is." I explain to everyone.

Ichika:(grabs Belt) Then we're just gonna have to go all out on her.

Sento: That's not an option. In order to draw out one's fighting instincts to the max, the Sclash Driver induces the body into the production of excess adrenaline. It puts a comparable amount of stress on the body as a result.

Kanzashi: But… Do we have any other choice?

Sento:(looks at Kanzashi) I've been looking into that. I recently found a hidden command in Katsuragi's research data. It's likely a power-up item for the Build Driver.(stands up) I just need to find the right keyword to unlock it and-

Ichika:(puts down belt) We don't have time for that. I'll make sure to beat her up for good next time.

Chifuyu:(stands up) Ichika! We aren't fighting this war in order to kill our opponents.

Sento: She's right. We're doing it to protect Touto.

Ichika looks at the two of us, and rolls his eyes before he turns away. "Sigh~ Either way, we're still going to be fighting." Ichika says, the two of us turn away from each other as the room goes silent… "Hey..." Tatenashi speaks up. "Where's Houki?" She asks, and all of us pause. Wait… Yeah where is she?

We are Houki

I'm knocked to the ground, I reach for my blade again, but as I try to lift it up my grip slips and the blade falls back down. Stalk sighs as she walks over to me. "Look, I think it's time we put a hold on this fight. We can finish this later." Stalk mutters before she turns to leave I try and reach out after her. Stalk walks over to the suitcase with the Sclash Driver and Jelly inside.

Stalk:(gestures to suitcase) Feel free to take the Driver and jelly with you. I don't have a need for it. It is made for you after all. Ciao.

Akats:(reaches out) S...St...Stalk…(passes out)

Time skip: ?

I sit up and look around to see that I'm back at IS Infinite Stratos Cafe. "You're awake, good." Sento says sitting in a seat next to the bed. I sit up, looking around to see that my belt and the Usa Hopper are sitting on the table next to the bed. "Houki… Where did you get this?" Sento asks me, I look over to see in his lap is the Case that holds the Sclash Driver and belt. "It's..." I begin to ponder.

Sento:(looks at Houki) Where did you get this?! Answer me.

Houki:(looks at sheets) It was Tabane… She gave it to me, and put me through a gauntlet to try to get me to use the belt.

Sento:(looks at Houki) I assume with you using the word "Try" means that you didn't use it?(Houki nods) Sigh~ Good. Everyone was worried when you didn't come back… Houki? You seemed concerned about something.

Houki:(shakes head) No, it's just I'm worried that Tabane will try and put us through a gauntlet of Smashes… That's all…

Sento:(nods) Yeah… But we'll deal with it as it happens.(pats Houki on the shoulder) Get some rest Houki.(leaves) You need it.

I lie back on the bed and turn away from Sento, the Uso Hopper jumping over to me and nuzzling close to me. I embrace the Hopper as I hide under the sheets. Why?... Why couldn't I tell him about the bottles?... I check my pocket to find the Sakura Bottle, I stare at it. "Kasumi." I mutter, a tear running down my face as I close my eyes.

The Next day… We are Observer

Touto Soldiers ducks back into cover. "Damn, we're at a stalemate here." A soldier says to another. "Yeah." Another soldier responds. From the distance behind the Hokuto army the walkers approach. "Armor division approaching!" A soldier screams out, everyone looks behind as tanks roll up and fire off their cannons destroying the walkers.

Elsewhere in Occupied Territory… We are M

I sit in the Barber's seat, having my hair cut shorter. All while staring at the image of Mii-tan on my phone. Mii-tan… I think to myself. "She's cute." The barber notes looking over my shoulder. "Right?" I respond, the barber continues as I look back at my phone. But… Why is she with Build? I think moving my hand. "Mam, please keep your head still. I don't want to cut you accidently." The Barber warns me. "Ah… Sorry." I apologise putting my head straight.

Akaba:(thinking) You know, with Mii-tan, you think she's Ichika's girlfriend!?

M:(stands up) Like hell he is!(everyone's surprise) Mii is… Everyone's idol!

Akaba: Sorry…

Kiba:(enters) We're back!... What's going on?

"Nothing… Sorry about that." I apologise picking up the stuff I knocked over and putting them back. "Ah! Bread!" Akaba and Kiba run over and dig into the bread and milk supplied to us. "I'll continue now." The barber says as he resumes. "So, why are we using Barber Kiryu as our hideout?" Aoba asks me, Akaba steps in.

Akaba: Don't worry, this is now part of Hokuto's occupied territory. Stalk recommended this place,(points at M) right?

M:(sighs) What she think though that odd brain of her's I'll never understand. But yeah, she recommended this place to us... So, did you find Build?

Kiba:(crosses arms in an X) Nope, we couldn't find a thing.(drops arms) Maybe he's hiding somewhere underground?

M: Who knows…(pat on the shoulder) Thanks…(looks in mirror)... I… Don't know what to say…

I look in the mirror to see my hair cut in a Mature Short Layered cut… "It looks great!" I exclaimed looking at myself. "I don't have to worry about helmet hair… Thanks!" I thank the barber.

We are Sento

Sento:(surprised) Utsumi-san is alive!?

Ichika:(surprised) How? Didn't you… you know?

Houki:(crosses arms) From what I saw, he was shot in the shoulder, if someone pulled him out and got the bullet removed he would survive. Though I guess now, he has a little chip off his shoulder against you huh, Prime Minister?

Gen:(scoffs) Back on topic… It's likely that he's the one who built the Sclash Driver using your research data. He was a talented scientist before he became my secretary. However, if Hokuto has the same weapon on their side. We're going to need something that will surpass it.

Sento: That's why I wanted to talk to you today. I'm trying to find a keyword to access the hidden section of the research data.

Gen:(ponders) Now that you mention it… You once mentioned to me, that you created some kind of forbidden item.

"A forbidden item?" Houki and Ichika ask in sync walking over. It's then that an explosion rocks the building. "Sir! The Trio and Grease are outside!" Yamada exclaims, Tatenashi, Kanzashi, and Chifuyu rush into the room. "You three with us!" Chifuyu exclaims pointing to me, Ichika, and Houki. We all look at each other and nod before we rush outside.

Outside… We are Observer

Outside, the Trio cleans up the remaining guards and Guardians. "How about you throw out another one?" Grease asks Castle. "Got it, coming up!" Castle says charging up a blast, only for a shot to hit Castle knocking him to the ground. "What was that?!" Owl shouts running over. Just then, Sento, Ichika, Houki, Chifuyu, Kanzashi, and Tatenashi arrive. Kanzashi is already in her IS, now sporting a Gauss Cannon, that's been remodeled to work with an IS.

Sento:(looks at Kanzashi) Well done with turning an enemy Gauss Cannon into an IS Weapon. Altho I have my reservations about the Tech, at least it's helping.

Kanzashi:(looks at Castle) Doesn't do much in the way of damage against the Trio though.

We are Sento

Sento:(looks at Grease) Better some than none.

Ichika: Why are you guys here?!

Grease: We wanted to pay our respects to the heart of the city. But this is perfect timing. I've got a question for you guys…

The air is silent, as Grease steps towards us. Even without seeing her face, I can tell that whatever she's going to ask is something serious. Especially if it warrants this much threatening Aura from her… I prepare my mind to whatever question she throws at us.

Grease: What's your relation to Mii-tan?!

…. Eh? "EHHHH~?!" Ichika, Houki, and I exclaim leaning back. "Haa~?" Kanzashi and Tatenashi asks confused. "Grunts~ Oh, great." Chifuyu sighs. "EEEEHHHH~?!" Hokuto trio exclaim, tripping and fall over in shock. "Mii-tan came to help you during that fight we had yesterday, right?!" Grease shouts, as we all recover and I ponder up a quick backstory.

Sento: Oh~ She's, um… Someone else.

Grease:(confused) Someone else?

Sento:(nods) Yup. She gets mistaken for her a lot. Truth is, she's from Germany with her twin sister. They came to the IS academy. She had a mix up and couldn't return to Germany with her sister and she's staying at my residency till I can get her safe transport back to Germany.(takes out bottles) Get it?

I open the caps on the bottle, as the three of us ready our transformations. "Pirate! Train! Best Match!" My belt exclaims. "Seriously?~ Damn… Altho I guess that makes sense." Grease contextualise in her head. "Akatsubaki!" "Dragon Jelly!" Ichika and Houki ready themselves. "Geez, I got all worked up for nothing! All right hype up again, one, two..." We ready our transformations while the team chant something about Mii-tan. God she's an idiot for Mii-tan. "Henshin!" Me, Ichika, and Houki exclaim as the armor materialises on us. "The Punctual Swashbuckler! Kaizokuressha!" "Dragon in Cross-Z Charge!" "Akatsubaki! Yeah!" We stand ready to fight. Grease snaps her fingers as Smashes and Guardians appears.

Chifuyu:(looks at Sento) Sento! You, Ichika, and Houki handle those four. Tatenashi! Kanzashi! We're watching their backs, understood?

Tatenashi and Kanzashi:(nods) Yes, Mam!

Grease:(cracks knuckles) Okay… I'm feeling better now. I'll crush you with my burning soulfire!

Akats and Cross-Z battle the Trio as I battle Grease. I swing at Grease getting a few hits on her before I pull back on my Platform Launcher. "Pirate Train!" I fire the ship and train straight at Grease who tanks the blow. "That's it?" She asks me. "Not convinced? Let me show you what I can do!" I say charging at Grease again. I snap my fingers as Cannons appear around Grease and begin to bombard her, she tanks the blow before firing back at the cannons destroying them. As she destroys the last one I charge in and jump as a wave of water appears below me and a ship of energy appears. I surf across the water slamming into Grease knocking her down. I turned around, then I grab the Anchor on the ship and throw it at Grease. The Anchor wraps around Grease, using her as the Anchor I steer the ship at her, I jump off the ship at it swing around her before the ship slams into Grease. I land on the ground and pull on the chian to see that she's still chained up. I swing my leg sending a small rail car into Grease knocking her off balance. Now! I swing Grease around several times in the air before throwing her into a building. I look over to Cross-Z and Akats, I see Cross-Z beating up the Trio as electricity beings surging around him.

Cross-Z:(knocks away Castle) I can feel power building up inside me!

Akats:(chases after Cross-Z) Ichika calm down! You're losing control!

Grease:(steps out) Hey now. You pulled off that move and now you're just think I'm out of the fight? How quick of you to assume.

Build:(takes out can) Oh, trust me. I didn't assume at all. Build up!

I shake the Can and crack it open, then into the belt. "Rabbittank Sparkling! Rabbittank Sparkling! Yeah Yeah!" I take out both the 4-Koma and Hawkgattlinger. I blast at Grease before I toss aside the Gattler and swing with my 4-Koma. Grease blocks with her bare hands. "Heh, as well forget my previous complaints. You have all kinds of tricks up your sleeve Build!" Grease says before knocking me back. "Maybe that's what interests Big sis… Well, not my concern. Cause now it's now my turn!" Grease shouts as she launches into me, ramming into me and then jumping off of me into the sky. Grease lands on the ground, her shoulder pads shift forward with the nozzle facing towards me. The Nozzel's pop out into Beam Sabers. Grease grabs both the sabers and ignites them, their gold blade are aimed at me. Grease charges me swinging with great form. I'm seeing the resemblance! Grease swings at me and I can't dodge in time. "Funnels!" My funnels deploy out into a shield that barely manage to blocks Grease's blades. "Tch!" Grease mutters as she backs up, I send my Funnels at her only for Grease to smile as she slams her fist into the earth. The ground shakes as claws burst out of the ground and grab my Funnels crushing them. Shit! Grease then inserts her Jelly into the Twin Breaker. "Single! Single Finish!" Grease blasts me down.

We are Houki

Cross-Z dodge and knock down the last Smash. "The hell? Our attacks aren't working!" Stag shouts. "What the hell are you guys doing? Sigh… Fine I'll be your opponent." Grease says as she readies her own attack. "Bring it!" Cross-Z shouts as he insert the Cross-Z Dragon into the Breaker. "Ichika stop!" I shout but it's too late. "Ready! Go! Let's Break!" Cross-Z attack only for the attacks of both Grease and Cross-Z to be blocked by someone in the way. Standing up from the smoke is Stalk.

Stalk:(looks around) Whoo~! You boys are sure going at it. I can FEEL! The adrenalin from here!

Grease:(sighs) Why'd you have to get in the way…

Castle:(slams fist against the ground) What's going on, Stalk-san!?

Stalk: Well~ I thought that this might be a good time to get a reading on everyone's Hazard Levels.

Stalks suddenly slides across the ground, first jumping over Cross-Z all while slapping him in the face, then around to Build, who she slaps his thigh, then to Grease where Stalk gets behind then shoves her arms into the chest plate of Grease and gropes her then to me, where she slaps my ass, then to the Trio and slapping the three on the back. "Why the face!?" Cross-Z shouts. "What the hell Prv!? And how did you even get at my boobs?!" Grease shouts in confusion, I sigh. "Of course it's either my ass or my chest." I groan. Stalk stands up and points to the Trio.

Stalk: Hokuto Trio! You're Hazard Levels are… Castle: 3.7! Owl: 3.6! Stag: 3.7! Grease: 4.2 and a fine set you have! Their modest, but FINE nonetheless. Build: 3.9 just SO close to 4. Cross-Z 4.0! And Akats… Well… 4.1. That's how strong you are at this point in time. Good thing about that gauntlet I put you though, you managed to pull close to Grease by .1! Sento, Ichika and Houki have surpassed you. You're going to have a tough time if you wanna stop him now… So let's put a lid on this today, Grease you and the boy's should head home now. I need to have a little talk with the Touto Riders here.

Akats:(confused) What? What are you talk-

Stalk then blasts into the ground as smoke fills the area. The smoke clears and Grease and the Trio are gone. Stalk still stands ready to battle us, we collect ourselves and ready. "Okay, let's get this ball rolling then huh?" Stalk says before she takes out her Steamgun and removes the Full Bottle inside and takes out a new bottle, the body and design is similar to that Kaizer Gear Bottles, but besides and even on the gear are a series of snakes. Stalk then inserts the bottle into the gun. "Cobra! Add on!" Music begins playing as Stalk points the Steamgun at us. Pulling the trigger smoke engulfs Stalk. "Boost! Cobra!" Electricity shoots out from the smoke before the smoke goes up in flames, and leaving Stalk in a new pair of armor.

Cobra's armor color changes. The Red of the armor goes white almost albino, with the green still being around on the chest and face, black. Floating around her back is a new pair of IS based wings, a cobra face peering from them. The waist now has drape with a snake scale outline.

Cross-Z:(looks at the Armor) Shit...

Build:(looks at Stalk) Figured she'd do something like this. Blend Steamgun Technology with IS technology.

Cross-Z:(materialises IS) You're not the only one who fuse IS and Rider Tech!

Akats:(takes out blade) It's 3 against 1 anyways, we're taking you down!

"Wanna text that Theory?" Stalk asks before she deploys her wings that change into cobra's that slam into Build and Cross-Z, sending the two away. Slamming the two into each other and dropping them. The Cobra's flies over to the disabled guardians and grab them, lifting up the bodies and attaching onto Guardians. The Disabled Guardians activate as they pick up the missing parts of their bodies and reattach them. "So, 3 on 1 huh?" Stalk mutters before the Guardian limbs attach and they cast off their clothes. The Cobra's then change into new armor on the Guardians. "Ladies and Gentlemen! And Ichika." Stalk says. "Hey!" Cross-Z exclaims.

Stalk:(gestures) Feast your eyes upon the Cobra Guardian!

The Cobra Guardian, have the same body as the Base Guardian, but the chest helmet, shoulder, and waist have all been changed. The helmet is changed to look more like Stalk, the chest having the cobra's face with the fangs out to the sides. The shoulders are also like Stalk, the waist has the tail wrapped around it.

The Cobra Guardian's activate and they grab the fangs on their bodies and remove them and they activate into Beam Sabers. They attack Build and Cross-Z and I look back at Stalk.

Stalk:(puts hands together) Shall we begin Round 2 then?

Akats:(clenched fist) Come on then. Let's dance!

Construct 71 Complete