This article, Gundam Build Fighters: Steel Builders, is property of FigureGunplaFan.

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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, and it was streamed exclusively at Bandai Japan's Youtube site.

The TV release of the ONA released for Asia countries, titled Gundam Build Fighters: Steel Builders ~Snap-on Edition~ (ガンダムビルドファイターズ: 鋼のビルダー ~スナップオンエディション~), which combines both 12-minute episodes (in chronological order) into one episode with an addition of fixed animation errors & newly animated footage. This version also aired in Disney XD Asia.


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


NOTE: Guest stars are in italics.

Steel Builders


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Yazan's gang

  • Yazan (Hochu Otsuka)
  • Gamon (Juurota Kosugi)
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Team Amethyst


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Team Eternal


Supporting characters



  • Meijin Kawaguchi the 3rd

Mobile Weapons

Steel Builders

Alexandra Siblings

Yazan's Gang

Team Amethyst

Team Eternal



Cameo MS

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


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.


In late 2016, an English Dub of the ONA was announced by Funimation, starting with the first reveal of Jamie Marchi voicing Aina.

In the same year, a Korean Dub was announced by Daewon Media.


Kitahara Tomoe provides the illustration for the manga adaptation of the ONA.

Sequels & Spin-offs


  • 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, Ains' father is probably 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. However, this might have implied that this universe and the Love Live! Reboot Series shared the same universe.

Build Fighters
Stories Regulation E - Episode Shino - Episode Monica | GBF: Another Age | The Runaway - The Returner | GBF SWF | GBF Junior | GBF Revolutions | GBF: A New World | Project Build Fighters | GBF: Steel Builders - ~One Year After~ - SIDE YAMATO - Gunpla CONCEPT - B2 | GBF eXceed | GBF Genesis | GBF Energy - Link Battle - New Link | GBF Extremer | GBF Overdrive | GBF Forever | GBF Survive | GBF Zero
Topics Locations | Technology | Model Suits | Characters
Other Timelines Universal Century | Future Century | After Colony | After War | CC (Seireki) | Cosmic Era | Anno Domini | Advanced Generation | Build Fighters | Regild Century | Post Disaster | SD Gundam | Galactic Colonization | Kidverse | Forgotten Era | After Destruction | Zero Era | Solar Era | Stardust Century | Diamond Era | Downfall Age | Nightmare Time