The Fedaykin were the guerilla fighters of the Fremen. The Fedaykin later became death commandos, who served as the personal bodyguards of Paul Atreides. After he became the Kwisatz Haderach, Paul led the Fremen to battle against the Sardaukar and Harkonnen. The Fedaykin served as the commanders of the Fremen army. After Paul defeated the Sardaukar, he became the emperor and launched a Jihad in his name. With the Fedaykin serving as priests and commanders for the Jihad, the Fremen were able to spread the religion of the Muad'Dib.