Temple Avesti, the most fanatical sect of the Universal Church, was originally called the Vesta Templa, and was founded as a Church order around 3000 A.D. with it's first temple/monastery on the planet Pyre. During the first century and a half of the Church (2850-3000), there was a tendency to combine the Vestic midwinter bonfire on various planets with the growing faith of the Universal Church.
Almost obliterated by the noble houses when their fanaticism went to far, they are now carefully watched by the Orthodoxy and are considered to be in a state of extreme penance.
Their mission is to seek out signs of sin and corruption within humanity and remove it lest it infect other innocents. Often their methods may be harsh and cruel, committing the body to the flame so that the soul mirror may be cleansed by the sacred fire of the Holy Flame.
Avestites are instantly recognisable by their blood-red asbestos robes and the oily smell of their flame guns. Avestites rarely receive warm welcomes by the communities and often travel in numbers for safety.
During therest of the Diaspora (until 3500) and through the Second republic (3500-4000), the Vestics developed a reputation as the fundamentalist wing of the Church, including it's Pyric Creed.
After the fall of the republic (4000) and into the early New Dark Ages, the Templa Vesta was somehow renamed the Temple Avesti. The Avestites attracted fanatical members of other Church sects (including Hinayana Orthodox clerics and certain Hesychast sects) who felt their Church neede to be more active in stamping out heresy and excessive high tech use. Avestites associated closely with the Church's Inquisition at this time.
By 4235, a space fleet by anti-Avestite nobles, guildmembers, and merchants came to Pyre to wipe outthe Avestites once and for all, but they were stopped by the official Church fleet.
As a result, Avestites were required to obey Orthodox clerics of equal or higher rank, which lasts to this day.
In the 46th Century, Avestites gained more control of the Inquisition and dominated it by 4600 A.D. In the early 50th Century, the Avestites were granted the right to use flameguns which they are now well-known for.
Avestites have various monasteries around the Known Worlds, and membership in Temple Avesti is largely based upon stern morality. The pilgrims of the Temple who roam the Known Worlds, often as official Inquisitors, have proven themselves morally and they usually carry flameguns.
The official head of Temple Avesti is also archbishop of Pyre, and other Avestite bishops have served as archbishop on certain other planets.