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Promise is the twenty-fifth and final episode of Gundam Build Fighters.


After many ups and downs, the finals of the Gunpla Battle Championship World Tournament are over at last. However, in its aftermath, the Plavsky particle crystals have gone out of control. The particles that fill the arena are starting to materialize, as the panicking audience members rush to escape. The only way to resolve the situation is to destroy the crystals. On Nils's advice, Sei and Reiji dispatch their Gunpla, as do Mao, Fellini, China, and Aila, but they are hard-pressed by the counterattack from the crystals. Their former rivals hurry to their aid, as do the former Gunpla fighters Mr. Ral, Takeshi, and Master Chinan. Let's do it! This is Gunpla's last shooting!


Around the building, crystalline growths of Plavsky particles erupt along the walls and support beams, threatening to collapse the entire building. Baker implores Chairman Mashita to stop the Arista, but it doesn't stop glowing. Takeshi Iori and Mr. Ral take it upon themselves to begin an evacuation of the audience, assisted by Luang Dallara and Greco Logan. The Gunpla Battle System activates, turning the interior of the arena into a space zone and materializing a representation of Zeon's final fortress, A Baoa Qu, much to the shock of Tatsuya YukiSei Iori, and Reiji

Even at 1/144 scale, the asteroid fortress is large enough to break through the dome of the tournament stadium. The gathered Gundam Fighters decided to evacuate, while Chairman Mashita comes clean to Reiji, apologizing for stealing the Arista and begging for his help.

Before the others can run, Nils Nielsen and Caroline Yajima arrive. Nils explains about the massive underground Arista and decides that before the now-unpredictable particle system can cause any more damage, he'll try to destroy the crystal. Unfortunately, the crystal has transported itself inside A Baoa Qu, and the only way to reach it at hand is to use a gunpla to breach the fortress since it is too dangerous to go in person. Reiji (with Mashita in a headlock) agrees to join Nils, along with everyone else. With the GP Bases still functioning, Reiji takes off in the still damaged GAT-X105B/ST Star Build Strike Gundam, Sei follows in his RX-178B Build Gundam Mk-II, China's KUMA-03 Beargguy III, with Aila Jyrkiäinen's new AC-01 Miss Sazabi, as well as Ricardo Fellini's Gundam Fenice Rinascita, followed by Kirara's AGX-04 Gerbera Tetra, Nils' 侍ノ弐 Sengoku Astray Gundam and Caroline's Knight Gundam. Tatsuya wishes to help, but his PPGN-001 Gundam Amazing Exia  is in no condition to fight. Fortunately, Allan Adams arrives with a repair kit. Outside, the evacuation finishes, but Rinko tells Takeshi that the children are still missing.

Back at the Arena, several Mock mobile suits, armed with weapons from across the Gundam saga, have launched from A Baoa Qu in response to the mobile suits approaching. To Mashita's dismay they are the new products that were intended to be announced after the tournament. The Gundam Fighters engage in a fierce battle, but there are far too many to punch through... until Mao deploys his newly-completed XM-X9999 Crossbone Gundam Maoh and blows a hole through not only the Mocks' line, but the fortress itself, giving the team a clear path inside. With a new opening present, Reiji and Sei head into the fortress, backed up by Aila and China while the others hold off the horde.

The mass of Mocks is endless however and threatens to overwhelm the fighters until Master Chinan and Mr. Ral arrive with their own Gunpla; a GF13-001NHII Master Gundam  and Ral's custom Gouf R35. Together, the two veteran builders show the full strength of their experience, tearing the Mocks apart en masse.

Inside the base, Aila suddenly notices a massive buildup of Plavsky particles as they head towards the fortress' core. The core is protected by a massive particle cannon. The beam fires, with Aila and China just barely managing to push the Star Build Strike and Build Mk. II out of the path of the blast. The massive beam erupts from A Baoa Qu, destroying everything in it's path. Both Miss Sazabi and Mr. Bearguy III are disabled, and more Mocks come pouring through the hole blasted in the fortress, pinning them against the cannon, which is charging for another shot.

Suddenly, Tatsuya Yuki tears through the Mocks with a repaired Exia in Trans-Am followed by Takeshi with the PF-78-1 Perfect Gundam. Figuring that the crystal has to be behind the cannon to power it, Takeshi destroys the cannon with a massive blast from the Perfect, giving the Star Build Strike and Mk. II an open path. With the girls' safety assured by Takeshi and Tatsuya, Sei and Reiji manage to penetrate to the crystal's chamber. However, it tries to push them away with a huge wave of plavsky particles. To fight the particle storm, Sei disengages the Mk. II's Build Booster and attaches it to the Star Build Strike, activating the RG system and giving them the power to push through and destroy the crystal with the Hyper Build Knuckle.

The shattered crystal explodes scattering particles everywhere as the Mocks shut down and the space zone and A Baoa Qu fade away. Chairman Mashita begins to glow, as the giant Arista is no longer anchoring him in this world. Baker desperately hugs onto him just as the effect triggers, pulling her to Arian with him. Recognizing the effect as the same one that happened with Reiji before, Sei worriedly turns to Reiji, only to find him perfectly fine.

With the particles disappearing, Reiji wants to have one last battle with Yuki, keeping their promise to have a great battle to show the world their love of gunpla. With both units heavily damaged, Fellini and Mao give the Fenice Rinascita's arms and the Crossbone Maoh's weapons to re-arm the Build Strike, while Allan hastily re-repairs the Exia with parts from the PPMS-18E Kämpfer Amazing. As the boys set up their gunplas, Kirara finds a camera and resumes broadcasting herself.

As their battle rages on, Yuki thanks them for providing a battle that he can truly enjoy. Sei thanks Reiji for taking over for his own shortcoming as a Gundam Fighter. Reji assures him that his only fault was worrying too much about damaging the model out of his love for gunpla, and that worry was holding him back. But thanks to the friends and rivals he's met over the course of the tournament, he's learned how to let go of those concerns and be willing to take a risk to earn victory. As his own Arista starts to fail, Reiji lands the Build Strike and turns the controls over to Sei.

Proving Reiji's point, Sei holds his own in battle against Yuki. But just as he manages to score an opening against him, the last of the particles fade, bringing the battle to an end. Reiji's Arista also gives out, and he begins glowing as well. Sei and Reiji say their goodbyes, with Reiji getting Sei to promise to get stronger so they can fight each other next time. With that, the Arista finally breaks and Reiji disappears.

Later, Reiji stands in the garden of the Royal palace in Arian, promising to see Sei again since they'll always be connected. To his great surprise, someone hands him his HG GPB-X80 Beginning Gundam model. It is none other than Aila, carried by the Arista passed on from Sei. Reiji is still remarkably clueless as to why Alia would wish to follow him to Arian, much to her annoyance.

A year later, everyone continues their peaceful lives. Kirara's career has taken off, with Fellini happily looking on. Mashita and Baker are selling Mock models in Arian, Master Chinan and Mao goof off with kitbashing random gunpla, Misaki's inn is once again full of customers, with Tatsuzo as a employee. Allan and Tatsuya show off Gunpla to children, Nils and Caroline have rediscovered Plavsky particles and a way to artificially synthesize them, ensuring that Gunpla Battle will continue. With Yajima Trading now sponsoring the GBWC, China, Mr. Ral, and Takeshi and Rinko look on as Sei prepares to keep his promise to Reiji to become stronger, defending his title in the 8th Championship with the new GAT-X105B/CM Build Strike Gundam Cosmos.

Featured Mobile Weapons




  • The Plavsky particle crystals forming in the arena are similar to the ELS from Mobile Suit Gundam 00 The Movie -A wakening of the Trailblazer-.
  • This episode marks the first time that Sunrise has re-animated A Baoa Qu since Mobile Suit Zeta Gundam. It also marks the animated debut of the PF-78-1 Perfect Gundam.
  • The Field 3 Forest generated in the very last battle of this series is the exact same field layout from episode 1. In addition, the Star Build Strike's movements mirror those used on its first match with Sazaki's Gyan in episode 1.
  • The sky above Arian indicates that it is most likely a space colony.
  • Kids resembling Setsuna F. Seiei and Lockon Stratos are shown as China attends Sei's qualifying match for the 8th Gunpla Battle World Championships.
  • Units from Season 2 of Gundam 00 could not be used in Build Fighters due to an agreement between Sunrise and MBS (the station that aired season 2) stating that they could not use units from shows airing less than five years from the show's airing. The final episode of 00's second season aired March 29, 2009, five years and two days before this episode's first airing on March 31, 2014, allowing Yuki's Exia to be fixed as a nod to the GN-001RE Gundam Exia Repair
Gundam Build Fighters Episodes

Sei and Reiji | The Crimson Comet | Full Package | Gunpla Idol Kirara ⭐️ | The Strongest Builder | A Reason to Battle | World-level Ability | Encounters of Fighters | Wings of Imagination | The World Tournament Begins | Battle Royal | Discharge | Battle Weapon | Codename: C | Fighter's Radiance | Dad, We Meet Again | Model of the Heart | Bloodhounds | Astray's Blade | Aila's Betrayal | Amid the Glittering Particles | Meijin vs. Meijin | Gunpla Eve | Dark Matter | Promise
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