- Written By: Shogo MutoDirected By: Kyohei Yamaguchi
Sento: Pandora’s Box, which contains incredible energy, has finally been opened. The extraterrestrial entity Evolt has used its power to achieve his complete form. Meanwhile, the memories of the Devil’s Scientist, Katsuragi Takumi, have resurfaced in the mind of Kamen Rider Build aka Kiryuu Sento.
Finally, Evolt has transformed into his Phase 4 form, therefore completing his body! Cross-Z, Grease, and Rogue, three strong Riders are no match against his true form! Can they stop Evolt who has regained the ultimate power he used to destroy Mars? Meanwhile, Sento has recovered his memories as Katsuragi once again…
Episode Tropes:
- A Form You Are Comfortable With: Evolt revealed that because he reached Phase 4, he can transform into a copy of Soichi without having to possess him (or anyone else he wants).
- Alas, Poor Villain: After spending so much time as the enemies of the Nascita group, both Fu and Rai die rather tragically this episode after failing to slow down Evolt in any capacity.
- Curb-Stomp Battle: You're lying to yourself if you thought anybody has a chance to fight Evolt's Black Hole form on equal footing.
- Deadly Upgrade: The Hell Bros get dosed with more Nebula Gas in an attempt to reach up to Evolt's level, but Utsumi warns them that they will die if forced out of their transformation. Which is what exactly happens to them.
- Enemy Mine: Utsumi offers an alliance between the Riders and Nanba Heavy Industries to defeat Evolt. The Riders (minus Kazumi) agree to it, but only if it would help rebuild the country.
- Foreshadowing: Evolt uses the Evol Trigger and the five panels of the Pandora Box the heroes left behind to produce a seventh panel and begins slotting in Smash Bottles and converting them into Lost Bottles, all of which will come into prominence in the movie.
- Genetic Memory: Ryuga has a vision of Evol's Black Hole form on Mars.
- Heroic Sacrifice: Admittedly, hero is a stretch for Fu, but he manages to save Ryuuga from a deadly Rider Kick at the cost of his own life.
- Karmic Death: After all the evil stuff that Nanba has done over the series (and even before the series), it is no surprise that he would get his Laser-Guided Karma and be executed by Evolt the same way he had Prime Minister Mido killed.
- Killed Off for Real: Fu and Rai Washio, as well as Jusaburo Nanba.
- Sanity Slippage: Utsumi seems to have lost some of his marbles near the end, and when he becomes Kamen Rider Mad Rogue, he goes Laughing Mad.
- The Starscream: Now that he has his Black Hole form, Evolt decides that he's more worthy of becoming the world leader and wants Nanba as his puppet.
- Villainous Breakdown: After seeing Evolt come into his office for the kill, Nanba basically begs for his life, even offering Nanba Heavy Industries to him. It doesn't work out.
- Wham Episode: A lot has happened this episode.
- Sento's reversion to Takumi Katsuragi has put a noticeable tension on his relationships.
- Evolt no longer needs a host body and can transform at will if he so chooses.
- Evolt stalks Utsumi the entire episode trying to get Utsumi on his side. Utsumi completely disregards the safety of the rest of the world once he processes that Juzaburo Nanba, the man who put him in his caged life, has been killed and immediately switches sides as he is rechristened as Kamen Rider Mad Rogue.
- As is mentioned in above tropes, Fu and Rai Washio are both killed in battle by Evolt's Black Hole form and Nanba is killed like a fly after begging Evolt to not kill him in exchange for his money or his company.
- The Worf Effect: Katsuragi can't handle the fast RabbitRabbit form like Sento could. Justified as the last form Katsuragi used before losing his memories was GorillaMond which functioned radically differently.
