When they built Cathedra, their original settlement, the life of the people of the Seven Mothers was paradisiac. And for centuries, the Order of Eternal Mercy mainly comprised law-abiding citizens and nobles.
But that was a long time ago. Things changed. When they began colonising other planets and went to war with the Iron Empire, everything became darker. Far away from Cathedra, the Sisters faced new perils and new enemies. Some Sisters started to fight dirty. The farther they were from Cathedra, the less support they received from their hierarchy. And so, many Sisters ended up fighting on their own to protect the innocents.
Facing street gangs, racketeers, corruption, a small group of Sisters went rogue so as to fight back on their own terms. They went underground, switch to less restricting uniforms, and developed a very unique fighting style , using two guns connected by a long chain that they would use as both range and melee weapons.
Despite being disowned by the Ecclesiarchy, they quickly gained a tremendous support from the poor and the weak.