I'm rolling around some concepts in my mind for /mydudes/

The Order of Redeeming Pain is built on the idea that the opening of Cicitrix Maledictum was the result of mankind's sins, and only through repentant suffering can humanity redeem itself and see the galaxy healed. Like all Imperial forces, this newly founded Order was stretched thin by demands for help by human worlds under attack. But the Sisters swore that they wouldn't merely save the people, they would save their souls.
For the Order of Redeeming Pain, victory in battle is only the first step. The sins of the people must be purged, starting at the top. The planetary leaders, and sometimes even high guard officers if their regiments were found wanting in battle, are invited to a secret council with the abbess. This simple trick sees them walk into the Order's Pain Dungeons. There the Sisters visit pain upon them beyond imaging. The methods are a strict secret, but they are always successful.
After emerging from the Pain Dungeons, those men and women are lit by a fiery commitment to the Order's cause. They will lead their people in mass self flagellation ceremonies. Those who resist are dealt with, and those who survive the ordeal begin to seek out those who ran or hid, to force them to expunge their own sins through agony.
As the Order's ships take off to save the next disobedient world, their ships are filled with converts who desire nothing more than to experience that divine pain again, and offer themselves freely to be installed in Penitence Engines, which the Order has in abundance. Some even offer themselves to become Arco-Flagellants, although the cyborgs fielded by the Order seem different in some way from those seen in other Orders