The classic currency. Usually involves eternal servitude or becoming a battery for the Abyss after death. Your "Firstborn": A trope for a reason. It represents your future and legacy. A "Small Favor":
The demon embeds a piece of itself inside the mortal host. The character gains continuous power but gradually loses control. Eldritch or monstrous fiends. demon deals guide
Shaving decades off your life in exchange for immediate power. The classic currency
The demon will deliberately misinterpret vague language to cause chaos. 3. The Parasitic Bond demon deals guide
: Historically, deals are sealed via oral or written pacts. In pop culture, this often occurs at a "crossroads" where a demon is summoned to grant a wish.