Demons, severed from their Creator, can no longer turn to him for aid. To compensate for that loss, they instead turn towards the persons inhabiting the world. They approach them, offering them aid in exchange for pieces of their lives.
As any good salesmen, Demons are adept at putting in loopholes and similar ambiguities in their own favour into a Pact. Carefully crafted Pacts are a valuable currency among the Unchained and are traded by specialized Agencies.
Nature
The moment a Demon Falls, he is able to enter Pacts. Some demons theorize that making pacts is very much like banking with the stuff of the universe: A sort of instinctual knowledge about how to transfer "funds" from one "account" (in this case, the entirety of a living entity's existence) to another. Others look at it like rewriting the code of the cosmos, creating a new program with data from another person. Another theory suggests that pact-making is a new ability with no direct analogue among angels or other agents of the God-Machine.
Workings
The process of forging a pact is a simple one: the demon offers a mortal the chance to gain something in exchange for something. Usually, the price is a part of the mortal's life, sometimes one the mortal would like to be shed of: an abusive relationship, a dead-end job, even a criminal act. If the human accepts the deal, the demon must present a contract, though this is a simple process since she can create one from any appropriate medium: Paper, flesh, stone or something similarly symbolic and enduring. It only takes a few moments to transform the medium into a fully-written contract. Once the terms are laid out (and the aspects totaled up), both parties sign and the pact takes effect immediately. Both parties have to sign from their own free will, otherwise, the document is invalid. The same goes if the document is ever destroyed.
The signing of the document effectively alters the code that makes up reality to replace the abused party with the demon. The demon's Cover gains the relationship with the abusive boyfriend, or the stalker, or the friend from whom a person has drifted over the years.
Bills of Sale
When a demon decides to trade his pact despite it not being outlined in the original draft, Agencies use bills of sale. A bill of sale is a magical-legal framework, a quasi-pact enshrining an existing pact, that gives up the demon's side of a pact to any demon who signs it to mark herself as the new owner. The process of making a bill of sale has more in common with creating a gadget than signing a pact- the demon giving up a pact writes the bill of sale. Bills of sale cause aetheric resonance like gadgets, so they are usually locked away in secure locations when not being sold. They do not have to stay near the pact they modify, and some demons attempt to con others by providing a bill of sale and then destroying the pact. Prudent buyers demand both halves of the paperwork before supplying whatever price has been agreed.
Promisory Pact
Pacts usually come into immediate effect, but like a banknote containing a promise by a treasury to pay the owner, demons can write activation clauses into their agreements to delay the pact's onset. These delays add more flexibility in how a demon uses a pact, making them more useful in trade with other demons. Some demons use promissory pacts to bargain for speculative rewards; agreements to take the signatory's firstborn child, or ownership of a business they don't yet own, for example. These kinds of pacts are difficult to enforce with Primum and require especially intricate wording.
Soul Pact
The ultimate form of the pact-crafting is the Soul Pact, that has to be signed in blood. In exchange for a service, the mortal gains the identity of the opposing party. For all purposes, he becomes the person, whose original soul is completly rewritten to become a complete Cover for the Demon in question. Only the truly desperate or the suicidal are open for a soul pact and once finalized, no known force can restore the original person (although some claim that the destruction of the document would result in a nullification of the pact and restore the person).
References
- DTD: Demon: The Descent, p.189-194