That One with the Best Match

That One with the Best Match (ベストマッチな奴ら) is the first episode of Kamen Rider Build. It features the debut of Build's HarinezumiTank form.

Synopsis
A mysterious object known as the Pandora Box was brought back from Mars. In effect, Japan was divided into three by giant walls produced from the box. 10 years have passed since that day. This story takes place in one of the city capitals, Touto. Mysterious organisms known as Smash are terrorizing humanity. A physicist saves people from the Smash and pursues the mystery hidden within the Pandora Box. His name is Sento Kiryu. People call him...the Kamen Rider.

Plot
Ten years ago, Japan became the first country to successfully send a manned probe to Mars. In what appeared to be the ruins of an extinct Martian civilization, an astronaut discovered a mysterious cube, which would come to be known as the Pandora Box. At the return ceremony for the expedition, a security guard suddenly rushed forward for the Pandora Box. As he touched the artifact, a flash of light erupted, and a massive wall rose from the ground, splitting Japan into three regions: Hokuto in the north, Seito in the west, and Touto in the east. The rising of the wall, now known as the Skywall Disaster, prompted regional tensions, dividing Japan even further.

In the present day, Touto's government is in possession of the Pandora Box, and has formed the Touto Institute of Advanced Matter Physics, headed by Gentoku Himuro, in order to decipher the artifact before foreign countries attempt to seize any of the three regions. There have been numerous reports of Touto citizens being attacked by strange creatures known only as "Smash", as well as a mysterious hero nicknamed "Kamen Rider" saving people from the Smash. While being interviewed by journalist Sawa Takigawa, Himuro is informed about Sento Kiryu, a researcher applicant with promising test results. Later that night, Takigawa is attacked by a Smash, but is saved by the Kamen Rider. The rider extracts something from the Smash using an empty full bottle upon defeating it, causing it to revert to a human form.

The next day, Sento awaken from his sleep as he reminded about some part of his past memories, including being experimented by scientists using gas masks, lead by a bat man. Upon awaken however, he saw his face being smeared by marker. Sento already know who did it, but temporarily diverted as the full bottle he extracted last night had been purified by Misora into Hedgehog full bottle. As Sento visibly excited, Misora was too tired to even respond to Sento, and go to his bed to sleep. In act of revenge, Sento then smear her face with marker (drawn many physics formulas) before leaving his base.

Cast

 * Sento Kiryu (桐生 戦兎): Atsuhiro Inukai (犬飼 貴丈)
 * Ryuga Banjo (万丈 龍我): Eiji Akaso (赤楚 衛二)
 * Misora Isurugi (石動 美空): Kaho Takada (高田 夏帆)
 * Nariaki Utsumi (内海 成彰): Yuki Ochi (越智 友己)
 * Sawa Takigawa (滝川 紗羽): Yukari Taki (滝 裕可里)
 * Eita Kawai (河合栄多): Tsukasa Honjo (本庄 司)
 * Gentoku Himuro (氷室 幻徳): Kensei Mikami (水上剣星)
 * Night Rogue (ナイト・ローグ):
 * Soichi Isurugi (石動 惣一): Yasuyuki Maekawa (前川泰之)
 * Masakuni Mido (御堂正邦): Norimasa Fuke (冨家規政)
 * Yoshiko Tajimi (多治見 喜子): Ryoko Gi (魏 涼子)
 * Build Driver (ビルドドライバー): KORBY (コービー)

Guest Casts

 * Shinobu Katsuragi (葛城 忍): Joji Kokubo (小久保丈二)
 * Masahiro Nabejima (鍋島正弘): Ichi Oomiya (市オオミヤ)
 * Shimizu (志水): Shohei Yamazaki (山﨑将平)
 * TV Announcer: Kenya Matsuki (松木 研也)

Suit Actors

 * Kamen Rider Build: Seiji Takaiwa (高岩 成二)
 * Night Rogue: Jun Watanabe (渡辺 淳)
 * Needle Smash, Strong Smash: Hajime Kanzaki (神前 元)

Full Bottles

 * Bottle used:
 * Build
 * Organic: Rabbit, Lion (in BuildPhone), Harinezumi
 * Inorganic: Tank
 * Night Rogue
 * Bat
 * Form used:
 * Build
 * RabbitTank, HarinezumiTank

Errors

 * While Sento is explaining his the mechanics to his Build powers to Misora, there is one shot of him all cleaned up, similar to the state he was while he was leaving his lab. This could be due to a mis-arrangement of footage shot before and after the lab explanation scene.