In expeditionary bases, a strict hierarchy prevailed. At the very top were the planners who organized subsequent conquests and raids. They formed a prominent group of decision-makers and visionaries—an aristocracy among all professional groups. Right after them were the explorers, known as Berserkers. Fearless warriors forming the crews of Invaders, they alternately inspired both fear and admiration in others. Everyone took them seriously, and no one dared to cross their path. Immediately following them were the guardians, responsible for maintaining order and security in the base. Frustrated and zealous servants, often ruthless executioners. The next in the hierarchy were the technical support staff, people like Jo—experts in dirty work and at everyone's beck and call. Responsible for the proper functioning of the entire system. Perhaps only the settlers, at the very bottom of the social ladder, had it worse. Their role boiled down to populating and exploiting distant, often nightmarishly inhospitable planets.