Contractors are individuals who have gained superhuman powers due to the appearance of the Hell's Gate and Heaven's Gate. The existence of Contractors is kept a secret from the general public by most governments around the world, but they are well-known to the higher echelons of society and in the criminal underworld.
Contractors possess two other traits that give them a rather sinister reputation: the need to perform Obeisance, which is a bizarre, obsessive compulsive "payment" for the use of their powers, and a generally pragmatic, logical world view. This is described by the Contractors themselves as a lack of emotion in general, but not much evidence exists to verify this claim.
Contractors are fully capable of experiencing emotions, but that those feelings do not play a prominent role in their thought processes. They are described as being totally rational, and totally amoral. The general rules seems to be that they feel no guilt, and they cannot form or retain social bonds. A normal Contractor cares, in essence, only about their own well-being, and everything is reduced to a cost/benefit analysis: Any other issues like laws, emotions, or the question of the sanctity of human life are irrelevant.