This rather sinister power group is somewhat unusual in that its members come from a cross-section of many factions, not just the Doomguard. Members of the Destroyers fraction founded the Harbingers, but the group also has strong support from the Guvners and Athar. A small number of Dustmen and Godsmen also take an interest in the group and lend occasional support. The whole point of the organisation is to bring about the end of the multiverse, one world at a time. The Doomguard members realise that everything can’t collapse into true Entropy unless everything is destroyed – including the Outer Planes. Since the Outer Planes embody the beliefs of the Prime Material, the Prime has got to go first.
Initially, the Destroyers who founded the group simply attempted to carry out genocidal wars on the various Prime worlds. Unfortunately, this quickly proved to be an expensive undertaking. They decided instead that they needed to find a way to get the worlds to end themselves, without creating an uproar and the residents getting all defensive about it. It was at this point that one of the members brought a member of the Fraternity of Order on board. It seems that this member was cataloging all the various apocalyptic myths of the Prime. However, she only wanted true ones and most worlds have as many stories about the “end times” as there are gods. The Harbingers offered to help the Guvner prove her theories by arranging to bring about the conditions of the prophecies and see if the world in question would, indeed, end. After a few successes, the God Slayers group of the Athar caught wind of the Group’s actions, and wanted in. After all, the end of a world usually involved the death of one or more so-called gods. And, even if a god didn’t die along with the world, they would surely be weakened by the loss of so many worshippers.
The Dustmen are interested in the actions of The Harbingers simply because of the sheer amount of death involved in an apocalypse. Usually, they are content to watch the destruction, but occasionally they will act as missionaries and prophets and attempt to ease people into the afterlife. The Godsmen that support this group act in a similar role. Rather than letting people sit around and hope for a happy ending, the Believers of the Source travel the world and motivate people to get their affairs in order so that they will get off on a better foot in their next life.
Source: Ken Lipka