The Coalition of Volunteers was formed after the devastating defeat of Rommel's 7th Panzer Division in the hands of Mass-Divers, who had enhanced Break Decal that allow their damaged Gunpla to regenerate. Disturbed by this event, Kyoya Kujo of force Avalon spoke to a member of GBN's administration, the Game Master, only to learn that the administration could not punish the Mass-Divers due to the Break Decal being invisible to all their investigations thus far. Frustrated over the lack of action, Kyoya and Rommel sought to take matters into their own hands.
To that end, Kyoya, with help from one of his Vice-Captains, Emilia, gathered some of the best forces and singular members to aid in this endeavor. The Hyakki declined the invitation as a member of the force was a Mass-Diver previously, and as the force was currently on a self-imposed suspension. However, the force's leader, Ogre, suggested the Build Divers as their replacement. Kyoya also supported Build Divers' participation. Thus, the Build Divers were invited despite Emilia's doubt about the force's abilities.
The Coalition's mission was to stop the plague of the Break Decals through identifying the mastermind distributing them. An agent from Rommel's force met with the mastermind, but was forcefully logged out after the mastermind refused to give him a Break Decal. The agent's forced logout point was later identified, and with the Game Master's help, the Coalition headed to the mastermind's hideout. Unknown to the Coalition, the mastermind was aware of the impending attack and was well prepared - a massive group of Mass-Divers were ready for the Coalition. Some members of the Coalition infiltrated the hideout, but were intercepted. Kyoya was trapped in a room with one of the mastermind's enforcers, while Ayame turned against Riku Mikami as he was being lead to the masterminds's precise location thanks to Sarah.
Following Rommel's orders, the defense team regrouped their formation and refused to back down. Meanwhile, the mastermind's three hired mercenaries were defeated by Kyoya, Shahryar, Tigerwolf and a repentant Ayame. Shahryar and Tigerwolf headed towards the base as Riku and Sarah confronted the mastermind in his room.  Riku and Sarah attempted to find out the reasons behind the mastermind's actions, but he refused to clarify, cryptically dismissing and criticizing the game and its players. Later, Tigerwolf, Shahryar and Kyoya entered the room, and the mastermind escaped when Tigerwolf jumped him, revealing that his actual look is that of a Guest Diver Haro.
The mastermind then launched in his MA-08 Big Zam and activated a new Break Decal, causing other Mass-Divers' Gunpla to fight on their own will. These Gunpla are also used to amplify and diffuse a powerful signal emitted by the Big Zam's Break Decal that threaten to destroy the entire GBN. Despite an all out attack by the Coalition, they fail to harm the Big Zam, but the tables turned when Riku's GN-0000DVR/A Gundam 00 Diver Ace suddenly unleashed a pair of special Trans-Am wings that nullified and reversed the Break Decal's effects. Tigerwolf, Shahryar and Kyoya then used their Gunpla's most powerful attack on the Big Zam, with Riku dealing the final blow. With the mastermind defeated (although his identity remains a mystery), the threat of Break Decal ended, and the GBN back to normal, Kyoya announced the end of the mission.
Celebrating the Coalition's victory at Avalon's Force Nest, Kyoya and Rommel told the gathered Divers that their mission was a success - though the mastermind escaped capture and his identity unrevealed, there had been no reports of harms by Mass-Divers.
Sometime later, when it was discovered that Sarah was an electronic lifeform and the cause of a new outbreak of bugs, a game-wide hunt for her begins. After Kyoya located her, he was convinced to hand her over by Rommel, who suggested reassembling the Coalition of Volunteers so that they can keep her in their custody. This was to allow an alternative solution, if found, to be considered before the completion of the administration's update patch, which would erase her. If no solution is found, Sarah would be handed over to the administration. Till then, the Coalition would protect her using any means necessary. With help from the administration, the reassembly of the Coalition was later announced game-wide, and its listed goal was to work with the administration to eliminate the threat of 'EL-Diver' (administration's name for Sarah) from GBN. Sarah was also shown to be under their custody, and this greatly upsets Riku.
When Riku messages Kyoya that the Build Divers have a way to save Sarah, Kyoya informs Rommel and Game Master about it, but they turn it down as it only had a 5% chance of succeeding. After receiving advice from Kyoya, Riku gathered some allies and challenged the Coalition to Gunpla Battle at Avalon's Force Nest. Kyoya accepts on behalf of the Coalition, leading to an uneven Flag Battle, where Build Divers and its allies have to rescue Sarah while avoiding being wiped out by the Coalition's superior numbers. As the battle begins, Rommel orders the surroundings of all the server gates to be guarded, both the land and air routes. He also instructed the widening of the search range to find the location of Build Divers and their allies and direction of attack. Lastly, he calls for the sealing of the lunar surface gates. The Coalition later detected 3 shuttles approaching from the air, and both Kyoya and Rommel are surprised by the opponents' use of atmospheric entry.
The Coalition's ground forces shot down the shuttles, believing they had taken out the Gunplas in shuttle number 3 in the process as the ZGMF-X20A-LP Gundam Love Phantom, XXXG-01S2龍虎狼 Gundam Jiyan Altron, RMS-117G11 Galbaldy Rebake, RGM-89BM Jegan Blast Master and RX-零 RX-Zeromaru began their assault. Meanwhile, PEN-01M Momokapool sneaked into the Avalon's Force Nest via an underground waterway, while GN-0000DVR/S Gundam 00 Sky took an alternative route. Eventually, Momokapool was spotted by Karuna, while 00 Sky was ambushed by Randy's team as the Coalition had expected the diversion tactic. During the fighting, Game Master went behind everyone's back and attempted to erase Sarah, but was stopped by Kyoya, who begged his old friend to see this through. Tigerwolf encountered Shahryar, angry and disappointed that he was siding with the Coalition instead of Riku. The two rivals subsequently fought with Tigerwolf emerging victorious. Shahryar then revealed he only sided with the Coalition so he could finally have an all out fight with Tigerwolf. As Shahryar was about to disclose where the Coalition's defenses are the weakest to Tigerwolf, Kyoya arrived in the AGE-IIMG-SV Gundam AGEII Magnum SV ver. to stop them. Despite the two rivals working together, Kyoya and his new Gunpla proved to be too powerful and the two were defeated. Kyoya then met Riku and 00 Sky.
As the battle raged on, it seemed that the Coalition would be victorious - Yukio's Jegan Blast Master was stopped by Emilia and her AGMF-X56S/a Impulse Gundam Arc, Rommel and his forces had surrounded Magee, Tigerwolf and Shahryar, Ayame and Koichi were pinned down and Riku's 00 Sky was no match for Kyoya's AGEII Magnum SV ver. Fortunately, the Build Divers' new ally, Hyakki, arrived in time to help, with Ogre and his Gundam GP-Rase-Two taking over the fight with Kyoya, finally giving Hyakki's leader his long-sought battle with the Champion. Despite his aggressive battle style, Ogre was still inferior to Kyoya and had to be saved by Riku. The two then team up but were still fought off by Kyoya. Kyoya then opened all communication channels, allowing the other divers to hear from Riku how Sarah had helped him grow. The other members of Build Divers also attested to the positive effects Sarah had on them. In one final attack, Riku and Ogre used their special moves and clashed with Kyoya's EX Calibur. With their power and determination, they overpowered and defeated Kyoya, allowing Riku to fly off and rescue Sarah. He dismissed his Gunpla after getting close to the Avalon's Force Nest, and as he does so, Sarah ran out and jumped towards him. The two caught each other in mid-air, followed by Mol catching and cushioning their fall. With Sarah in Riku's arms, Game Master finally saw the "light of possibility" that Riku clung to and declared the match over in Build Divers' favor.
- ↑ Gundam Build Divers Episode 9, Return of the Ogre
- ↑ 2.0 2.1 2.2 2.3 Gundam Build Divers Episode 10, Coalition of Volunteers
- ↑ Gundam Build Divers Episode 11, Ayame's Tears
- ↑ 4.0 4.1 Gundam Build Divers Episode 12, Shining Wings
- ↑ Gundam Build Divers Episode 13, Duel
- ↑ Gundam Build Divers Episode 21, Your Feelings
- ↑ Gundam Build Divers Episode 22, Devoted Heart
- ↑ 8.0 8.1 Gundam Build Divers Episode 23, The Fateful Two
- ↑ Gundam Build Divers Episode 24, Decisive Battle