Gjallarhorn is a peacekeeping organization established by the nations of Earth. Its origin can be traced back to the Calamity War roughly 300 years ago. To prevent humanity from facing extinction due to the long lasted Calamity War, a group of like-minded individuals from across all nations and power blocs gathered together to end the fighting. To that end, they developed the Alaya Vijnana System and the Gundam Frames to possess the decisive edge necessary to end the war. They later became the organization known as Gjallarhorn. Gjallarhorn successfully ended the Calamity War and using their military might to maintain peace, they keep an independent eye on the four economic blocs that they established with the cooperation of Earth leaders. In the Post Disaster era, Gjallarhorn will go through the means of violence to maintain peace. They possess many mobile suits and had monopolized the technology required to produce Ahab Reactors. Unfortunately, the organization has become corrupted.
Commander of Mars Branch, Major Coral Conrad stages an assault on the CGS base in order to kill Kudelia Aina Bernstein so the tensions between Earth and Mars thickens. After failing, he sends Crank Zent to eliminate the CGS base leaving no evidence about their defeat, but this also fails. McGillis Fareed and Gaelio Bauduin arrives at the Gjallarhorn's Mars Branch headquarters for inspection. Coral attempts to bribe them but was rebuffed by McGillis. During a sortie around Mars' orbit, Coral ended up being defeated by the Tekkadan.
Despite this, in order to maintain the status quo, Gjallarhorn continues to harass Kudelia and her escort, the Tekkadan, and had attempted to wiped them out through intermediates and tried to capture her on the Dort Colonies. However, thanks to the machinations of McGillis Fareed, Gjallarhorn failed to prevent Kudelia from reaching Arbrau; instead, Gjallarhorn's attempt to interfere with Arbrau's prime minister election was exposed, leading to its neutrality among the economic blocs being questioned. This led to all four economic blocs deciding to develop their own military forces.
Gjallarhorn has three established branches: Earth, Mars, and Jupiter. Coral Conrad was the commander of the Mars Branch, while Ein Dalton is an officer from the Mars Branch. Crank Zent and Orlis Stenja were also officers in the Mars Branch. Gjallarhorn has a large influence on Earth and in space. An audit branch is also part of Gjallarhorn, which conducts routine inspections of the Gjallarhorn branches, making sure there is no corruption and efficiency in the organization. McGillis Fareed and Gaelio Bauduin are commanders in the audit branch. Although Gjallarhorn is a powerful organization that seems to flow seamlessly, there seems to also be some mistrust within, especially between the Mars and Earth branches, as Earth soldiers consider Martian soldiers inferior.
According to Naze Turbine, the Gjallarhorn forces in the Earth sphere (which includes the space colonies) are much better trained and motivated than those of the Mars and Jupiter branches. In addition, there exists within Gjallarhorn an elite moon-based unit known as Arianrhod, a fleet that is dedicated to protecting the Earth Sphere. There is also the Outer Earth Orbit Regulatory Joint Fleet, which is tasked with defending the earth's orbit but it is viewed by some as just being around for show. In fact, due to the rapid response of the Arianrhod Fleet to any threats to Earth, the Outer Earth Orbit Regulatory Joint Fleet and their Graze Ritters had next to none sortie record and thus had no combat experience. As a result, they suffered dearly in their pursuit against the less armed, but more experienced Tekkadan pilots.
The Seven Stars (セブンスターズ Sebun Sutāzu?) is a group of seven family clans that managed the Gjallarhorn for years. Amongst them, the Issue family is the strongest, while the Warren family were hit by a scandal involving illicit dealings with a economic bloc which brought misery to them several years ago. The current leader of the Fareed family, Iznario, tried to gain more power by turning himself into the legal guardian of Carta Issue (the Issue family's lone daughter), and by arranging the marriage of his adopted son, McGillis, to the Bauduin family's daughter, Almiria. He also has a secret pact with Henri Fleurs, and supported her election campaign to be the prime minister of Arbrau. However, his plans were foiled by McGillis, who was also trying to gain more power so as to fulfil his own goals of reforming the Gjallarhorn that he felt had become corrupted. Iznario was then forced into exile, and McGillis became the new leader of the Fareed family. To achieve his goals, McGillis also sacrificed the life of his friends and comrades including Gaelio (Bauduin family's heir and Almiria's brother) and Carta. All these caused a disruption in the power balance within Gjallarhorn, and allows McGillis to rise to power.
Known families and their members include:
- Issue Family: Carta Issue
- Fareed Family: Iznario Fareed, McGillis Fareed
- Bauduin Family: Sir Bauduin, Gaelio Bauduin, Almiria Bauduin
- Warren Family: Volco Warren
Gjallarhorn has a rank structure not based on insignia but by uniform and colors. Junior officers such as Ein Dalton wear a light purple uniform. Middle grade officers will wear a blue and white uniform without the cape. Ranking branch commanders like Coral Conrad wear a red uniform. Higher ranking commanders such asMcGillis Fareed and Gaelio Bauduin wear a blue and white uniform with a cape over the left side and a small sword on the left as well. The higher the ranking, the more lines a soldier will have on his/her cuffs and his/her shoulders, which are of gold color for all uniforms. A higher ranking commander will also have the front flap of the uniform folded back to the left in a triangle. For foot soldiers, there exists two uniforms, one consists of a plain blue and white uniform with a visored helmet while the other is a black and gray sealed suit with body armor and a closed helmet intended for heavy combat.