Ryn inserted Cortana's chip into the back of the armor's head, and Cortana promptly took over Kamen Rider Build. The Valkyrie battlesuit was now completely Ryn's toy.
Then, the red and blue lights in Kamen Rider Build's eyes shone brightly.
The blue right eye flashed, and Cortana's voice came from within the armor.
"Now, this lady is Kamen Rider Build."
Then, the red left eye flashed, and Ryn's voice emerged.
"Get lost, get lost, we're not doing that Rabbit-and-Dragon thing."
"Why not? When we get stronger, we can just make a Cross-ZBuild form. We've already got Build, wouldn't it be a disservice not to make the final form!"
"That's true, Cross-Z Build form is super cool! But I wonder if it can reach the level of strength from the tokusatsu show's setting."
......
"But since Cortana is here, I'll leave the transformation sound effects and special effects to you from now on."
"Sure. Do you want my original voice, or the one from the show?"
"Can't we have a duet? Wouldn't that sound better?"
......
Watching one battlesuit being split between Cortana and Ryn, with one person playing two roles...
Otto asked Kika curiously, "Is he always like this?"
"Yeah, this is his normal state. His brain has always been a bit off. But he's dorky and cute, and I like him just the way he is." Kika sat on Sabayon, quietly watching Ryn and Cortana's split-personality antics and their attempts at changing into other forms.
"Tsk tsk tsk... the stench of love. Your Sabayon and Nexus are far superior to the fourth-generation God-Slaying Armor, so I won't give you a set. However, the floating fortress being equipped for you is already under construction. Now take your Ryn and get out of here!"
Otto interrupted Ryn's transformation show and kicked both of them out of Helheim Labs.
Standing at the entrance of the lab, Kika tapped Ryn with Sabayon, signaling him that he could stop.
In just a few minutes, Ryn had transformed into all the Best Match forms, most of which were so bizarre that Kika couldn't bear to look.
"What kind of Best Match forms are these? They're so ugly... don't transform into them again..."
"Really? They're a bit ugly, but their functionality is pretty good. Fine, if Kika doesn't like it, I won't transform into them anymore."
Ryn removed the inserted Fullbottles, then kneaded all 60 Fullbottles on his body into one, creating a large, multicolored Fullbottle—the Genius Fullbottle.
"What a waste of all my forms... I made Otto work so long for nothing."
"Um... you could just not transform in front of me. Why destroy them all?"
"To show my true feelings for Kika~"
"Id... iot..."
——————————
Their promotion ceremony was over, and the S-rank armor was in hand. Theresa grabbed Kika and Ryn by the ears and dragged them back to St. Freya High School.
"Wow! It's Kamen Rider Build!!"
The moment she saw Ryn's armor, Kiana's eyes turned into stars, and she leaped at him.
"Ryn, this is... so cool! Can it change forms? Does it have a transformation pose? Like... like this!"
As she spoke, Kiana got into a wide stance, crossed her hands, then placed her right hand on her waist while her left hand swept up past her face, then made a large circle to join her right hand in front of her waist.
"Kamen Rider, henshin!"
"It does! It not only has poses, but it has transformation sound effects too!"
With that, Ryn removed all the Fullbottles, and the armor dissipated.
He then placed the custom-made Kamen Rider Build Driver in front of his waist, and a belt emerged from the driver, fastening itself around Ryn's waist.
"Now, let the experiment begin."
Ryn took out two Fullbottles, Tank and Rabbit. As he began to shake the bottles, mathematical formulas started appearing out of thin air around him.
Then, Ryn inserted the Rabbit and Tank Fullbottles into the driver and cranked the handle.
"Rabbit—" "Tank—"
As Ryn cranked, Rabbit and Tank began to fuse. Experimental pipes emerged from the driver, and red and blue half-armors appeared in front and behind him.
"Are you ready?" (Cortana's voice with an electronic reverb)
Ryn crossed his arms over his chest, then threw them open.
"Henshin."
The red and blue half-armors slammed together, enveloping Ryn. As steam hissed from his body, the armor completely sealed, and Kamen Rider Build was born.
"The formula for victory is set—"
"Wow!!!" "So cool..."
Now, Higokumaru and Bronya couldn't sit still either. The two of them turned into little fangirls and pounced.
"No, no, don't come over yet!" Seeing the three of them rushing over eagerly, Ryn quickly waved his hands to stop them.
Bronya and Kiana slammed on the brakes, but the silly Higokumaru...
"Ouch, so hot—"
Higokumaru, being able to fly, pounced first and was immediately sent jumping by the hot surface of the armor.
Bronya and Kiana, who had stopped just in time, froze in place. A built-in high-temperature buff? How cool!
But more important than that was clearly Higokumaru. The two turned to check on her.
"You idiot... it was just steaming so much, of course it's hot..."
Ryn canceled the transformation and used Honkai energy to cool down the frantic Higokumaru.
"Aren't you a Herrscher too... can't you cool yourself down..."
"Um... would you believe me if I said I can only breathe fire?"
"Useless..."
After confirming that Higokumaru was fine, the group became lively again. Bronya and Kiana fought over who would get to transform into Kamen Rider Build first, but neither would give in.
Kiana and Bronya started by arguing about who would transform first, then moved on to what delicious food to have Mei make for dinner, and finally ended up arguing about why their team had lost a match.
Ryn wanted to break up the fight, but Higokumaru quietly pulled him aside.
"Let them fight, let them fight... hehehe, more for me. Ryn, quick, quick, let me have a go before they notice!"
"Cutting in line is not good behavior... henshin!"
As Cortana's voice sounded, the driver in Ryn's hand flew aside and transformed on its own.
"What's there to fight about with transformations? It's better if I just do it."