The Xibalan were Camazotz that had dedicated themselves to the Wyrm through the tainted aspect of their patron, Bat. Since the disappearence of the Camazotz, they have not been seen. Their Kinfolk, called Bloodbats, continue to hound the South American rainforests.
Xibalan cropped up in every Camazotz community around the globe. Their numbers waxed and waned with the internal struggle of the Bat totem. If Bat fell into depression, the Xibalan became more powerful and hounded their Gaian brethren who tried to calm Bat. If the part that was loyal to Gaia was dominant in Bat, the numbers of Xibalan shrank. They saw these periods of service to Gaia as short intermezzos, akin to brief periods of daylight, and saw it as their spiritual duty to bring Bat back into the night and the service of the Wyrm.
The struggles between the Camazotz and the Xibalan were hidden from the rest of the Changing Breeds. Most often, Xibalan grew around small cults dedicated to blood magic who fell prey to the whispers of the Wyrm. Seeking to expand their numbers, the Xibalan prosetylized in secret to bring the rest of their breed into the Wyrm's service.
Ironically, the Camazotz of South America, the one's exterminated in the Second War of Rage, were the one's most resistable to the Xibalan's corruption. Their death strengthened the fallen werebats to a point that they joined their Totem directly, pushing it further and further into the Wyrm's embrace, fighting the remaining loyal Camazotz colonies in open combat. When Bat finally fell, the Xibalan flew into the Malfeas to join him there. No one has ever heard of them since.