So Cristos is mebbe/probably Black Council. I mean, we all suspect he is. And he basically blackmailed his way onto the Senior Council. He took over for LaFortier, who was the representative of the Eastern wizardry. Who feel that they are under represented and resent the Western parts of the Council for this.
No one's heard from the Jade Court vampires for a long time. The stick to themselves, etc. And Mavra is Black Court. I get the impression that they are more Eastern Europe based. Mavra has extensive magical skills. She's a witch of great power.
I think there's a big connection between the Eastern Court vampires and the Black Council. I think the Eastern wizardry, or some of them anyway, are planning a revolution. And that's the Black Council's purpose. And the Eastern vamps are working with them.
on an unrelated note: I just outed myself as a slasher to my little sister. :)