Technology & Combat Characteristics
After defeating the Innovades who falsely claimed to be Innovators, Celestial Being continued to exist as a deterrent force for the world, but it avoided conspicuous armed interventions as much as possible. This is because armed interventions using the Gundams have taken on a greater meaning, and might even trigger unwanted military expansion. Thus, Celestial Being now intervenes only when the Earth Sphere Federation government could not manage the situation, and actively uses mobile suits other than Gundams, but the use of Gundams is unavoidable for some missions., so Exia Repair III adopted a particle storage tank, also known as large GN Condenser or simply GN Condenser, as its power source. Additionally, GN Condensers were built into the enlarged shoulder and knee armor to boost the supply of GN Particles, and thrusters located in various parts of the body were changed to the latest model, making it possible for Exia Repair III to engage in high mobility combat and accelerate efficiently using fewer particles. The Exia Repair III is stationed on Earth and the 00 stationed in space, this arrangement is because Earth Sphere Federation's strict monitoring and full control of the Orbital Elevators made it impossible to transport the Gundams between Earth and space.
History
Sumeragi Lee Noriega explains the mission to Setsuna F. Seiei and Lockon Stratos. An Earth Sphere Federation research institute on Earth is secretly reviving the Super Soldier project. Notably, they are trying to create Super Soldiers by forcibly awakening Innovator-related factors. In a sense, these Super Soldiers can be described as artificial Innovators. The project is highly feasible as there are many commonalities between Super Soldiers and Innovators. Currently, a small number of people in the world have awakened as Innovators. The research institute forcibly gathered and experimented on people with such "talents" and those who have the Innovator factors. Celestial Being cannot turn a blind eye to the use of people with the "Dialogue" ability as tools of war.
After hearing Sumeragi's explanation, Lockon notes that Allelujah Haptism would have wanted to the join the mission if he is still here. Setsuna then volunteers for the mission, and Lockon agrees as Setsuna is an Innovator himself. With a smile, Sumeragi informs Setsuna that the GN-001REIII Gundam Exia Repair III is ready for his use. Sumeragi had anticipated that Setsuna would be executing the mission, so she had Ian Vashti prepared the Exia Repair III beforehand. Upon arriving at the sniping point as indicated by Sumeragi, Setsuna deploys the targeting scope and fires the Exia Repair III's GN Long Rifle. A particle beam shoots out from the weapon, but it only flies close to the edge of the buildings of the research institute, and did not hit any.
The defending mobile suits immediately launch and head for the Gundam's location, but Setsuna is unfazed as it is all going according to plan. A few minutes later, alarms sounded as chaos erupted in the research institute. The people with Innovator factors have begun their escape. Setsuna is not surprised by this turn of events. He had infused the particle beam fired earlier with a telepathic message containing information about his mission. The particle beam is composed of GN Particles, so it can be used as a medium for quantum brainwaves communication. Naturally, the sender and receiver of the telepathic message must have quantum brainwaves. In other words, Setsuna's earlier beam shot was for communication, and the people with Innovator factors within the institute successfully received his message and acted accordingly.
The Exia Repair III stands up as the mission entered phase two, and its GN Long Rifle folds in half as Setsuna prepares for melee combat. The Gundam then charges towards the enemy mobile suits – 12 GNX-609T GN-XIIIs. To buy time for those with Innovator factors to escape and increase their chance of survival, Setsuna has to keep the enemy mobile suits occupied for a while longer. Knowing the enemies are no match for him and his beloved Gundam, Setsuna unfolds the blade of the GN Sword Kai and calmy cleaves apart the first GN-XIII that approaches him.
Later, during the ELS Conflict, Setsuna was said to have used Exia to land on Earth. Presumably, this referred to the Exia Repair III.
Leos Alloy arrived in the simulation of the Anno Domini timeline sometime after the conflict in AD 2312 and before the appearance of the ELS. To obtain data on the Innovators, Leos wanted to isolate Setsuna, so he leaked two rumors to Celestial Being: one of a group trying to manufacture artificial Innovators and another of a terrorist group in space. As he predicted, Setsuna requested to do the former mission solo and departed with the Exia Repair III, while Lockon was sent out in the GN-006/SA Cherudim Gundam SAGA to deal with the latter.
Upon reaching the location, Setsuna and his Exia Repair III were attacked by a stolen GN-002RE Gundam Dynames Repair piloted by Leos. The fight was later interrupted by EX- and his Extreme Gundam Tachyon Phase, which held the head of the Cherudim SAGA in its hand. Though confused, Setsuna closed the distance and engaged Leos in close combat, easily knocking the Dynames Repair's GN Beam Saber away. This forced Leos to switch to the Extreme Gundam Type Leos Xenon Phase, and he quickly sliced the Exia Repair III's left arm. Soon after, Tieria arrived in the CB-002/GD Raphael Gundam Dominions to assist Setsuna. Realizing EX-'s actions was now distorting the timeline, Leos retreated while Tieria and Setsuna left to report the situation.