The Cab Driver did it all.
The Game is easy to understand.
The Cab driver is Cain. It is not a possesion, it is Cain himself. The only way to prove that is to play as a Malkavian. But it is Cain who brings Gehena.
Ghena is the end of the Bastard clans. Cain brings the Sarchogus into the fore in order to create dissent among the local factions. You as the player are the bringer of Gehena. You destroy all but those factions Cain wants left alive.
The Mummy that was in the coffin is the Assyrain King Messerack, he is sitting dead next to Jack in the end cut. In walks Cain and Jack says "it happend just like you said. " You can see the black lines eminating from him in the cut scene.
So you see it was Cain all along who moved and influenced you. Cain choose the Anrchs because he himself was the Original Anarch when he broke God's commandment and killed Able his brother. He advise you and moves you to side with the anarch or die with the rest. Its a great game- Hope you enjoyed it as much as I have.