Gundam Zodiac

In the beginning of time, Astraea created the 12 Zodiac Courts, which are for the 12 strongest constellations to sit in and rule a period of time.
The 12 Zodiacs were decided by a ritualistic battle between the 88 constellations with their own Gundams similar to the Gundam Fight, which is held once per zodiac rotation. In the year 2354, when mythological communication became a thing, the 12 Zodiacs as we know today were interacting with mortal humans to correct their errors of their destruction to the Earth. However, Ophiuchus isn't buying the ideals of the 12 Zodiacs and decided to hold a rebellion against them with the other 75 constellations, thus creating the First Astral Conflict.
In 2355, only 21 constellation Gundams, including all the 12 Zodiacs, are known to be operational and not sealed for eternity in the stars.