From Beacon:
Originally a charity dedicated to helping outlier farms recover after periods of heavy rain, the Sons admonished Temperance’s sinful history and spoke of an inevitable reckoning, where the wicked and lazy would vanish into the turmoil of the Pandaemonium. They preached how years of rebellion against the Imperium and the foul acts of past millennia created the Mind-Mould, something that made little sense given the frontier world’s relative short history. Soon after that, the bombings began. Specially-designed explosives and spore bombs detonated across Bastion and Beacon in a campaign of terror that lasted weeks. The subsequent mould infestations cost the lives of thousands, but wherever the infections flared, the Sons of Temperance emerged to ease the suffering of the afflicted.
When the population of Temperance’s newest city, Thirdstone, disappeared overnight, the Sons claimed the event as vindication of their beliefs. Beacon elevated many of the cult’s leaders to positions of prominence, as scores of fearful farmers bolstered the cult’s ranks, opening themselves to the wisdom of the cult’s “prophets.” From that fateful day forward, the cult has only grown, and now the Sons’ ranks outnumber those of the Bastion Deputies. Reluctant to turn the unrest into a full-scale civil war, Proctor Vigdis maintains a level of patience with the Sons’ activities. Moreover, with Adeptus Ministorum representation on Temperance abnormally low since the Thirdstone incident, she needs someone to manage the spiritual wellbeing of her people, and until the Pandaemonium subsides and greater numbers of colonists arrive, the Sons of Temperance remain her only choice.