The Valkyries were the elite fighting individual or unit of the combined Honored Matres and Bene Gesserit group, the New Sisterhood. The fighting unit was perfected by the Sisterhood's merger/founder, Murbella, and involved combining the best of both organizations. A Valkyrie combat troop was trained in the ways of the Gesserit with intense Prana-bindu training, using that kind of nerve and muscle technique, with the speed and ferocity of the Matres. Few opponents were able to withstand against a Valkyrie troop or unit.
Murbella used Valkyries to re-capture Buzzell and Tleilax away from the rebel Honored Matres groups, which would not unite with the New Sisterhood. On Tleilax, especially in Bandalong, the rebel leader Hellica was quickly overwhelmed and surprised by the effectiveness of the Valkyrie unit, as the Sisterhood re-took that world.