ADEPTA SORORITAS
The Adepta Sororitas, also known as the Sisters of Battle and formerly as the Daughters of the Emperor, are an all-female division of the Imperial Cult's ecclesiastical Adepta known as the Ecclesiarchy or, more formally, as the Adeptus Ministorum. The Sisterhood's Orders Militant serve as the Ecclesiarchy's military arm, mercilessly rooting out corruption and heresy within humanity and every organisation of the Adeptus Terra. There is naturally some overlap between the duties of the Sisterhood and the Imperial Inquisition; for this reason, although the Inquisition and the Sisterhood remain entirely separate organisations, the Orders Militant of the Adepta Sororitas also act as the Chamber Militant of the Inquisition's Ordo Hereticus.
The Adepta Sororitas and the Sisters of Battle are commonly regarded as the same organisation, but the latter title technically refers only to the Orders Militant of the Adepta Sororitas, the best-known part of the organisation. The Sisterhood serves as the Ministorum's only official military force because the Decree Passive laid down by the reformist Ecclesiarch Sebastian Thor held that in the wake of the Age of Apostasy's Reign of Blood in the 36th Millennium, the Ecclesiarchy cannot maintain any "men under arms."
This command was supposed to limit the power of the Ecclesiarchy by preventing it from maintaining the massive armies of the faithful Frateris Templar it once used to abuse its power from the 32nd to the 36th Millennia. However, the Adeptus Ministorum has been able to circumvent this decree by using the all-female military force of the Sisterhood's Orders Militant.
The Adepta Sororitas are an elite sisterhood of warriors raised from infancy to adore and worship the Emperor of Mankind. Their fanatical devotion and unwavering spiritual purity is a bulwark against corruption, heresy and alien attack, and once battle has been joined they will stop at nothing until their enemies are utterly crushed. Battle-Sisters will stride through fire if need be, their Bolters spitting staccato bursts of destruction every step of the way. Not even death can stay the wrath of the Adepta Sororitas -- indeed, the blood of martyrs only strengthens the resolve of Battle Sisters, spurring them to greater acts of heroism in the name of the honoured fallen.
The Adeptus Ministorum -- or the Ecclesiarchy as it is generally known in the Imperium -- is a monolithic state church founded on the worship of the God-Emperor as the saviour of Mankind and the preaching of the Imperial Creed throughout the whole galaxy. The Sisters of Battle are the army of the Ecclesiarchy. Clad in ceramite Power Armour, they carry an awesome array of weaponry with which to vanquish their enemies; the incredible wealth of the Ecclesiarchy ensures that they are equipped with the best wargear the Imperium has to offer. The Sisters of Battle are trained to the peak of human ability and stand amongst Mankind's most dedicated and disciplined warriors. Wherever there are foes of the Emperor, the Sisters of Battle will be found fighting with faith and steel. When not actively prosecuting the Ecclesiarchy's wars, the Battle-Sisters of the Orders Militant divide their time between rigorous training and devout worship of the God-Emperor.