Gundam Build Fighters: Steel Builders

Gundam Build Fighters: Steel Builders (ガンダムビルドファイターズ: 鋼のビルダー, also known as GBF:SB) is a Japanese science fiction 12-minute anime web series based on Sunrise's long-running Gundam franchise. The series serves as a spin-off to the Build Fighters series. The series ran for at least 2 seasons.

A TV release of the ONA is currently planned.

Summary
A trio of three young Gunpla Builders who took many Gunpla Battles, with their kits only equipping physical weaponry.

Characters
NOTE: Guest stars are in italics.

Steel Builders

 * Kenji Tsukiyama (Katsuyuki Konishi)
 * Ringo Akisawa (Aya Endo)
 * Ains Mittelman (Yuki Kaji)
 * Chisato Himawari (Kaori Nazuka)
 * Takumi Murasaki (Tetsuya Kakihara)

Alexandra Siblings

 * Natalie Alexandra (Miyuki Sawashiro)
 * Leo Alexandra (Ryohei Kimura)

Yazan's gang

 * Yazan (Hochu Otsuka)
 * Gamon (Juurota Kosugi)

Team Amethyst

 * Aina Kirishima (Megumi Han)
 * Reika Murasaki (???)
 * Jin Kazama (???)

Team Eternal

 * Yamato Hoshikawa (Yoshitsugu Matsuoka)
 * ??? (Tomatsu Haruka)
 * ??? (Kanae Ito)

Others

 * Crank (Yasuhiro Mamiya)
 * Ami (Nitta Emi)
 * Chan Syaorin (Vivian Hsu)
 * Kenji's class teacher (Shuichi Ikeda)
 * Mr. Mittelman (???)
 * Mrs. Mittelman (Ayahi Takagaki)
 * Kenji's class teacher (Shuichi Ikeda)
 * Mr. Mittelman (???)
 * Mrs. Mittelman (Ayahi Takagaki)
 * Mr. Mittelman (???)
 * Mrs. Mittelman (Ayahi Takagaki)

Cameos

 * Meijin Kawaguchi the 3rd

Steel Builders

 * ASW-G-08/K Gundam Barbatos Kenji custom
 * EB-06R-1 Graze High Mobility Type
 * EB-05s/R Schwalbe Graze R
 * MS-06R-1A/SB High Mobility Type Zaku II Ains custom
 * RX-77-2/SB Guncannon Steel Builders custom

Alexandra Siblings

 * AMS-119 Geara Doga Natalie custom
 * AMS-129 Geara Zulu (Guards Type) Leo custom

Yazan's Gang

 * ASW-G-11BW Gundam Gusion (BW)
 * RX-139EX Hambrabi Kai

Team Amethyst

 * ZGMF-XX09T/AMT DOM Trooper Aina custom
 * ZGMF-1017AS/AMT GINN Assault Type Team Amethyst custom

Team Eternal

 * ZGMF-X10A-ET Eternal Freedom Gundam
 * GAT-X105-ET Eternal Strike Gundam
 * ZGMF-X56S/θ-ET Eternal Destiny Impulse Gundam

Other

 * GAT-01A1/C Dagger Close Combat type
 * Zakusaurus Rex
 * Tricera Gundam
 * RX-178 Gundam Mk-II Kenji Version
 * RX-178+FXA-05D Gundam Mk-II + G-Defenser Kenji Version
 * RX-178 Gundam Mk-II Kenji Version Physical Weapon Type
 * RGM-79 GM
 * RGM-79 GM Ringo Version
 * ASW-G-66/KAC Gundam Kimaris Aina Kirishima custom

Cameo MS

 * EB-06 Graze
 * GAT-X1022 Blu Duel Gundam
 * ZGMF-X20A Strike Freedom Gundam
 * EB-AX2 Graze Ein
 * ZGMF-X20A Strike Freedom Gundam
 * EB-AX2 Graze Ein

Production
Asako Nishida (Love Live! School Idol Project) serves as the main character designer of the series, rather than Kenichi Ohnuki & Suzuhito Yasuda.

Yuki Hayashi will compose the music for the series, along with Masaru Yokoyama.

Sequels & Spin-offs

 * Main Articles: Gundam Build Fighters: Steel Builders ~One Year After~, Gundam Build Fighters: Steel Builders: SIDE YAMATO, Gundam Build Fighters: Steel Builders V-A

A sequel film is currently in production.

A prequel spin-off manga, Gundam Build Fighters: Steel Builders: SIDE YAMATO is currently being published in Gundam ACE.

Trivia/Notes

 * Yuuhei Murota was originally meant to be the character designer of the series, but it was replaced by Asako in the last minute change.
 * Despite this, the character designs for the series is very close to Yuuhei's art style.
 * Continuing the trend of deceased Gundam characters being reincarnated in the Build Fighters Universe:
 * Crank was based on Crank Zent from Gundam Iron-Blooded Orphans, while his nephew Ains Mittelman loosely resembles Ein Dalton.
 * However, there are hints of Ains' father is actually a reincarnation of Ein himself.
 * Chan Syaorin is based on Chan Agi from Mobile Suit Gundam: Char's Counterattack.
 * However, there are several characters based on their original Gundam Multiverse counterparts who haven't died:
 * Yazan & Gamon is based on Yazan Gable from Z Gundam & Gemon Bajack from ZZ Gundam.
 * Yamato Hoshikawa is based on Kira Yamato from Gundam SEED.
 * Some of the characters from Love Live! made cameos in the series.