The Cult of Transcendence is said to be a cult led by Nyarlathotep, dedicated to bringing about the Endtimes. It's headquartered in Stockholm, Sweden. It is supposed to have a network of front organizations that span the globe, and to be allied with other cults, including the Secret Senate and Enolsis. Like the best conspiracies, little has been revealed, and nothing is known for sure.
The Cult of Transcendence is described in the Targets of Opportunity sourcebook.