The Reaver fleet was stationed in the Reaver space above the planet Miranda. For years, they would sporadically send raiding parties out to Rim planets and distant territories. When Malcolm Reynolds provoked the Reavers by blowing up a crab-shaped vessel, most or all of the Reaver fleet pursued Serenity in unison. They followed Serenity until they passed through the ion cloud above Mr. Universe's planet, where they confronted—and were eventually destroyed by—a large Union of Allied Planets fleet in the Universe battle.