Nice. Well organized and thoughtful. I can't wait to see how you develop these guys more.
Some thoughts and suggestions:
-Stray away from absolutes. Instead of saying all, say most. It makes you sound more credible.
-Instead of appearing all of a sudden, which is cliche, perhaps a revision to the following: "200 years ago the other Kabals took notice of...", or some such.
-Being made up from all social strata makes your Kabal seem very gang-like. Even with Vect's coupe, status is important in the Dark City. If that's what you're going for, awesome! And if it is what you're going for, expand on it. Make it yours and run with it.
-Details are your friend. The more the merrier. How is the Mirror Archon's armor resplendent? Is it super shiny? Is it made from a rare metal? Etc.
-Going back to the absolutes. If your Kabal had secrets on everyone, someone would eventually consider you too big of a risk and simply wipe you out. Go with generalities again. Your Kabal treasures secrets and rumors. Your Kabal has dirt on many Kabals. Perhaps even your Kabal does the dirty work for other Kabals in exchange for secrets and whatnot.
I love your impregnated poison thing on your armor. It adds a nice personal touch. I love your Kabal's rules in a tome bound in the skin of traitors. It needs a name. Something that epic deserves a name. Like the Manifest of Blahblahblah. Obviously, Blahblahblah is not cool, but you know what I mean.
Another Vect hater tickles my cockles so. Yes. Tickles them.