Templar-esque Cult members who bury the dead and preach new hope to the world. They are the army of 'light' in a world of darkness.
Founded somewhere in Utah, the Crusade (called the Crimson Crusade due to the blood-red cloaks worn by their Priests), send out their numbers to civilize the wild, to bring order to Chaos.
This would happen as early as 1 year after the "collapse" and is generally something that would be found where you find lots of "unprocessed" corpses.
The Crimson Crusade is made up of Priests, Templars and Missionaries - a religious movement that asserts order in the chaos of the Collapse. Members of the crusade, wearing white hooded cloaks and tabbards marked with the red cross, can be found in any place where the dead lay unattended. Their missionaries will collect the dead for cremation and set them alight after a long ceremony that begins at dusk. They and the Priests burn the dead to ensure that they can not come back from the grave (an early practice from when Vampires would embrace randomly to spread the chaos of their blood in the ruined cities.
Their steadfast calm and orderly ways is sometimes seen as reassuring by those who are still confused by the disastrous collapse of society. Missionaries work collectively to restore order and society by sharing food from "parish" to "parish". Priests work to maintain order once the Missionaries have began the process of conversion. Templars are the militant arm of the Church - defending their churches and their followers from all manner of assault; including the nightmares that walk on two feet.
The missionaries are quick to become the civic leaders of small communities, normally organizing themselves around the template of a Church. Extra supplies are shared by neighboring parishes to maintain their order for to many of the survivors; food can buy loyalty.
Crusaders, however, approach the reconstruction of their world a bit differently. Crusaders, as one can imagine, a militant Order. They hunt out the uncivilized, godless, heathen survivors to teach them the errors of their ways - most of the time at the point of a spear.
Missionaries are commonly sent from well-established parishes to stretch out their teachings. In those places where Missionaries are welcomed the Crusaders, usually on horseback, are rarely seen except to "show the flag". If Missionaries are refused or worse, attacked, the torch-wielding Crusaders attack in mass; their faces obscured by a crimson scarf within their hood.
The image of the cross is commonly affixed at the top of a long lance, the entirety painted a rich crimson. These lances are normally set out at crossroads and well-traveled paths to show the extent of their progress.
The missionaries preach from the newly written "Book of Ashes "; a sort of biblical re-write to show the changes and the "wrath" of the Creator upon the world.