- Written By: Shogo MutoDirected By: Satoshi Morata
Misora: A civil war has erupted over the incredible energy hidden within Pandora's Box. In order to fight off an invasion by Seito, Kamen Rider Build aka Kiryuu Sento takes Pandora's Box back from them. Meanwhile, Sawa discovers that Banjou has extraterrestrial DNA.
Sawa: Misora, how should we tell everybody about Banjou?
Misora: Maybe we should keep it like Sup alien dude!
Sawa: That's a terrible idea!
Misora: Then maybe serious like, Banjou, you are inhuman.
Sawa: Alright, when you put it that way it sounds like an insult.
Misora: Look, the intro's about to end.
Sawa: Now what'll happen on Episode 32?!—-
- Amnesiac Hero: While not as bad as Sento, Sawa and Sento theorize that Blood Stalk must have removed most of Banjou's memories after he settled in with his relatives once his parents were dead.
- Brutal Honesty: Sawa tries to discreetly find a way to let Sento the truth of Ryuga's being in the opening, and once Sento reads Ryuga's records for himself, he just says it upfront with no fanfare to Ryuga's face.
- Delayed Reaction: After Ryuga trashes Blood Stalk as Cross-Z Magma, he realizes he forgot about Rogue. Then Sento has delayed reaction to the realization of that.
- Early-Bird Cameo: Blood Stalk possesses a mysterious Cobra Fullbottle-like object in his hand that is for the "Ultimate Driver".
- Even Evil Has Standards: Gentoku ultimately choose not to kill Kazumi's workers. His reasoning:Rogue: Your plan failed. There's no point in killing them.
- Hostage for MacGuffin: Nariaki (with Hard Guardians and Rogue in tow), calls Kazumi and arrange for him to steal Pandora's Box in exchange for the safety of the rest of his workers. However.....
- I Am a Monster: Ryuga does not take it well when he finds out that he is a alien, even questioning his humanity.
- Pet the Dog: When it was clear that Kazumi wasn't going to show up with Pandora's Box, Gentoku...cuts the bindings off the hostages and lets them escape.
- Phlebotinum Rebel: While most Kamen Riders are this, Ryuga embodies the trope in this episode by stating that if he and Blood Stalk have the same kind of power, even if he was not human, he will use his power to oppose Blood Stalk in the name of love and peace since that is the kind of Kamen Rider he believes in.
- Shoot the Hostage Taker: Of all people, Gentoku attacks the Hard Guardians and Nariaki. According to Gentoku's logic, since Grease didn't show up, the hostage negotiations became pointless and weren't necessary.
- Suicidal Pacifism: When Taizen demands to end the war or risk using Pandora's Box in retaliation, Nanba disguised as Mido points out that he is too much of a Technical Pacifist to consider attacking Seito.
- "World of Cardboard" Speech: After spending most of the episode grappling with the revelation that he isn't human, Ryuga delivers one to Blood Stalk, affirming that he is a Kamen Rider and that he will fight for love and peace regardless of whether he's human or whether he shares Stalk's power.