A deal with the Devil, pact with the Devil, or Faustian bargain is a cultural motif widespread in the West, best exemplified by the legend of Faust and the figure of Mephistopheles, but elemental to many Christian folktales. In the Aarne-Thompson typological catalog, it lies in category AT 756B – "The devil's contract."
According to traditional Christian belief in witchcraft, the pact is between a person and Satan or any other demon (or demons); the person offers his or her soul in exchange for diabolical favors. Those favors vary by the tale, but tend to include youth, knowledge, wealth, or power. It was also believed that some persons made this type of pact just as a sign of recognizing the Devil as their master, in exchange for nothing. Regardless, the bargain is a dangerous one, for the price of the Fiend's service is the wagerer's soul.
The pact can be oral or written. An oral pact is made by means of invocations, conjurations, or rituals to attract the demon; once the conjurer thinks the demon is present, he/she asks for the wanted favour and offers his/her soul in exchange, and no evidence is left of the pact; but according to some witch trials and inquisitions that were performed, even the oral pact left evidence, namely the diabolical mark, an indelible mark where the marked person had been touched by the devil to seal the pact. The mark could be used as a proof to determine that the pact was made. It was also believed that on the spot where the mark was left, the marked person could feel no pain. A written pact consists in the same forms of attracting the demon, but includes a written act, usually signed with the conjurer's blood