The cult was composed of people dedicated to worshiping Ruby Eye Shabranigdu. It included humans, beastmen, chimerae, and even a middle-ranking mazoku. The cult had completely taken over the town of Mane; it is implied that all of the townspeople were members.
The cult stole a Claire Bible manuscript from a shrine in Raizeel and used it to create two sets of Zanaffar armor, with the intention of using Zanaffar to destroy Saillune. Their plans met with interference from Lina Inverse and her friends, as well as from Zelgadiss Graywords and Xelloss, who were pursuing the manuscript for their own purposes.
By the end of The Silver Beast, all of the high-ranking cult members are dead. Xelloss also threatened to kill a large part of the Mane townsfolk when they attempted to attack Lina's group, but she convinced him to disable them instead.