- Written by Shogo MutoDirected by Shojiro Nakazawa
Sento: Why do I have to run while doing the introduction? Kamen Rider Build, the brilliant physicist Kiryuu Sento, we've learnt Banjou was framed by Stalk... Whose identity is the man I'm chasing right now!
- Battle in the Rain: Sento and Soichi begin and end their battle in this episode in the rain.
- Big Damn Heroes: Ryuga steps in to try to fight Blood Stalk in Sento’s place, but ends up being forced out of his transformation after taking a point-blank Steam Attack.
- Breaking the Fourth Wall: Sento delivers the recap while chasing after Soichi following the end of the previous episode, and sounds like he is actually running and getting tired while delivering the exposition.
- Brick Joke: Once again while Ryuga is relaxing, his zipper drops open again.
- Curb-Stomp Battle: Once Sento decided to use the RabbitTank Sparkling FullBottle, the battle took a decisive turn and Sento proceeded to completely dominate the fight.
- Deep Sleep: Continuing off of the exposition from #5, Misora apparently was found unconscious in the room Pandora’s Box was kept in before the Sky Wall Incident, and was kept in a hospital for a few years until she was abducted around the same time as when the two panels of Pandora's Box were taken from the laboratory.
- Escape Call: To buy time to build his special power up to use against Blood Stalk, Sento makes Ryuga take Misora out for another date.
- Fakin' MacGuffin: Even though Sento lost the Octopus and Light FullBottles, the rest of the FullBottles that Soichi stole at the end of the last episode were fakes that Sento prepared beforehand.
- Father, I Don't Want to Fight: Sento can’t focus on his fight because deep down, he really doesn’t want to hurt Soichi, the man who made Sento the person he is.
- The Gloves Come Off: After hearing Soichi’s reason for his entire scheme, Sento decides he has had enough, saying that he and Ryuga truly became heroes of their own volition to protect others, and then breaks out the RabbitTank Sparkling FullBottle.
- Hair-Trigger Temper: After triggering the Sky Wall Incident, Soichi apparently was known to fly into wild rages to the point he had to be taken away to an underground hospital.
- Hand Signals: Sento and Ryuga have this exchange with each other when Sento forces Ryuga to take Misora out for another date.
- Locked Out of the Loop: Misora was intentionally kept in the dark about Soichi’s betrayal by the rest of the nascita crew to keep her from stressing out over it.
- Pragmatic Villainy: Soichi delivers a Breaking Speech saying that the reason why he used Sento to become Kamen Rider Build was so that Misora could return to purifying the essences that Faust needed as FullBottles for their grand scheme involving Pandora’s Box.
- The Reveal: A lot of things get explained in this episode, like part of what happened to Soichi between the Sky Wall Incident up to now, why Soichi used Sento to become Kamen Rider Build, and the In-Universe reveal of Night Rogue’s identity to the protagonists.
- Stuff Blowing Up: Ryuga is subject to a handful of FullBottle energy explosions trying to find a Best Match that works with the energy from Pandora’s Box.
- Super-Empowering: One of Sento’s essence gathering FullBottles absorbs residual energy from Pandora’s Box after Blood Stalk’s attack, which would later be converted into the RabbitTank Sparkling FullBottle.
- The Teaser: We see the end of Sento and Soichi’s chase and Blood Stalk ends up walking away with all of the FullBottles and Pandora’s Box before the show cuts to the opening.
- Was It All a Lie?: Soichi responds to this question saying that no, not all of it was a facade and there were even times when he was genuinely proud of them. Despite this, he still doesn't hold back against Sento and Ryuga.
- Wham Shot: Soichi jumps out of the alley once he decides it’s time for him to leave, untransformed.
- Where It All Began: Sento and Soichi decide to have their showdown in the alley and nearby warehouse where Soichi first found Sento.
