The contract has been practiced since antiquity. The Horas or Hybridas involved work under the allegiance of Mer . According to legend, Merlyn was the first human to make a Pactus Infernus, possibly with Mer himself. Legend also states that he bargained for both immortality and reality warping and the workings of the universe. Mer may have granted him all of these in reward of being the first human to accept the contract, and possibly out of amusement too.
The kinds of power that can be gained seem to be limitless, although it often depends on the Hora/or sometimes Hybrida involved. So far the following exchanges have been confirmed:
- Immortality- Only the oldest Horas retain the secret of true immortality, Salvia is so far the only known Hora who holds the forbidden knowledge in creating the Elixir of Immortality, also known as the Philosophers Stone. Though the mortal who becomes immortal is not damned, as their immortality allows them to escape death and never therefore be able to enter the Nether. However all their decendants, no matter their deeds, will be damned. Damien is the only confirmed character who became immortal this way, though he unintentionally entered into the contract that was originally meant for his father, nevertheless he entered into the contract and is the only child to do so. Since the catch behind the contract is to send the immortal's decendants to the Nether, this part of the contract became null since Damien became immortal at the age of 10, making him incapable of having decendants, but keeping him immortal and preventing him from entering into the Nether. However, the Hora involved in the contract do have the power to break the seal of their immortality (which is typically a fragment of the Hora's soul bonded to the immortal's soul, ripping it out would release them from the mortal plane). Because Salvia has mixed feelings of motherly love and ownership over Damien she has refrained from doing so.
- Workings of the Universe- This exchange gives the mortal knowledge out of this world, however it is so vast that it often drives them insane unless they are very strong willed. At the end of their mortal lifespan they will be damned to the Nether .
- Reality Warping- They can manipulate Physics, allowing them to not only bend, but even break the laws of physics. Being the general form of reality warper, 'Physics Manipulators' can invent their own physical laws and impose them on the rest of the universe. This type of exchange became outlawed back in ancient times because the mortals posessing such power posed a threat to Mer himself, it is an illegal contract no known Horas or Hybridas are believed capable of doing anymore. Back when it was allowed, the mortal given such power would be damned to the Nether at the end of their lifespan.
Willbending- So far only seen in Earth 2, the power allows the user to manipulate the will of other mortals, and if practiced enough, allows them to control their mind. Only mortals can have their mind controlled, it bends the will of immortals but cannot fully control their mind. Damien of Earth 2 obtained this power but was saved from damnation with the mercy of Jal .