Cultists that have risen up in Briarstone Asylum, apparently centered around patient Ulver Zandalus. They wear yellow bedsheets and a flame symbol on their foreheads made with chalk.
After Dora experienced her psychometry vision of Dr. Losandro's office, she came to understand that they served the Tatterman, not Ulver Zandalus, and had possibly been converted to the worship of Hastur.
In Chapters 23 and 24, the party encountered a small group of Apostles engaged in some heavy self-medication.
In Chapter 26, the party encountered a large encampment of Apostles stationed in the asylum’s Great Hall and kitchen. Their numbers were in the range of 40-50, and they were eagerly waiting for a “sign” that the way to the “meat” in the chapel was open.
First Reference: Chapter 10
Other Notable References: Chapter 15, Chapter 22, Chapter 23, Chapter 24, Chapter 26