The Brotherhood Without Banners, led by Berric Dondarrian and Thoros, the Red Priest, are an outlaw troop, travelling the Seven Kingdom's and delivering the King's Justice.
Hearsay and gossip are important elements in this series. Characters' legends and infamies grow and spread throughout Westeros by word of mouth. What we read chapter to chapter can and often does get distorted as word travels until what we know and what they know are two vastly different truths. In the second and third books, villagers spread the legend of the Lightning Lord, whose band of outlaws strikes against enemies of the late King Robert without warning and cannot be kept dead. Of course, the best tales hold a kernel of truth, and in Berric's case, much more than that.