Adepta Sororitas image - Sanguinius

The Adepta Sororitas (also "the Sisterhood" or "Daughters of the Emperor") are an all-woman subdivision of the religious organization known as the Ecclesiarchy or Ministorum. The Sisterhood's Orders Militant serve as the Ecclesiarchy's fighting arm, mercilessly rooting out corruption and heresy within humanity and every organization of the Adeptus Terra.

There is naturally some overlap between the duties of the Sisterhood and the Inquisition; for this reason, although the Inquisition and the Sisterhood remain entirely separate organizations, the Orders Militant of the Sisterhood also act as the unofficial militant arm of the Inquisition's Ordo Hereticus.

The Adepta Sororitas and the Sisters of Battle are commonly regarded as the same thing, but the latter title technically refers only to the Orders Militant, the best-known part of the organization.

The Sisterhood serves as Ministorum's only official military forces because the Decree Passive rules that the Ecclesiarchy cannot maintain any men under arms. This was supposed to limit the power of the Ecclesiarchy. However the Ministorum were able to circumvent this decree by using the all-female force of the Sisterhood.