The Saint Seth cabal is a one-human-body cabal, comprised of all the people who are renting space in Pope Fay's brain. Because of this, no: you cannot join. Why would you want to? Pope Fay has other cabals you can join if you're interested.
Why is it called the Saint Seth Cabal? Because we wanted to name the cabal after a famous multiple group, and the only two we could think of (and knew their names) were Sybil and Seth. Since Sybil was a very negative stereotype and nothing at all like us, we chose the more positive Seth. Because while we may not know much about that particular multiple group, what we do know is that it's a more positive multiple group to have as a collective Saint than Sybil. Because we know a few things about that group from the Multiplicity LiveJournal community.
Well, it turns out that Seth was not a multiple group, but rather a channelled entity. Oh well. I'm not changing the name.
Since I've already listed the members, I guess there's nothing else to say about it.