Brother Joe was a middle-aged black man, lean, with a small potbelly and a salt-and-pepper beard. He was very intelligent and well-educated.
Brother Joseph, or Bro Joe, was the "spiritual leader" for Soulardville. He was, in actuality, a man who had an affinity for devices; one day, he discovered that using sub- and supersonic frequencies could attract and repel screamwings. He was driven out of his original ville shortly after this (because of the incessant attacks) and wandered the wilderness for a time, where he became a preacher of sorts. He fashioned a staff with the device attached to it, then found Soulardville, which had a huge screamwing nest nearby. He demonstrated his control over the creatures to the baron, who (despite being a nice guy) saw the need for the occasional sacrifice or punishment by screamwing to keep everyone else in line.
The baron's daughter was next in line to be sacrificed, so she ran off. The companions were hired to find and bring her back, which they did, but Joseph refused to honour the deal the baron had made with them, so they broke out, taking Joseph with them. Along the way, they discovered his secret. They headed to the screamwing nest, left Joe there to be eaten alive, and torched the place, killing him and the screamwings (Playfair's Axiom).