Bene Gesserit
Violent and without mercy, the Matres possess military and sexual skills that seem to indicate to some that they are an outgrowth from or a combination of the Fish Speakers and Bene Gesserit who fled out into the Scattering. They do not, however, possess Other Memory or use melange, though their skill as sexual imprinters has surpassed that of the Bene Gesserit. The Matres target the Bene Tleilax, and capture and torture as many Bene Gesserit Reverend Mothers as possible to glean their secrets. Similarly, the Bene Gesserit hope to decipher their new enemies' motives, and learn enough about the fearsome Matres to defeat them.