No, not a cult. We're Assassins, operating in the shadows to protect humanity from the Templar Order who would seek to take Free Will away and control the world as they see fit. It has been a shadow war that has been raging for millennia, stretching back to the ancient world, perhaps even as far back as the First Civilization.
Considering the carnage I saw him inflict upon London, Jack should've stayed in the asylum. It is one thing to try and help someone. It is quite another to take a mentally ill boy and train him to kill efficiently.