Spacing Guild
In the series, the "native" Fremen of Arrakis live in communities called sietches, each with its own naib leader who has ascended to the position by challenging his predecessor and proving himself the strongest in the tribe. The Fremen system of justice relies primarily on trial by combat, and individuals may challenge each other hand-to-hand duels to the death over matters of etiquette, law, or honor. The victor of these challenges becomes responsible for the wife, children, and certain possessions of the defeated. The Fremen pay enormous spice bribes to the Spacing Guild to keep the atmosphere of Arrakis free of spy satellites, and they have a long-term plan to terraform the planet.