Within a month, Black Mask had assembled dozens of petty criminals around Gotham into what he referred to as the False Face Society, using the Sionis crypt as his base of operations. Each member of the False Face Society wore a distinctive mask (presumably from Sionis' own collection), which Black Mask promised would allow them access to baser instincts and more powerful identities. The False Face Society spread rapidly through Gotham, eventually attracting the attention of both the police and Batman.