Petitioners are people who are experiencing their afterlife. They might have died on the Prime Material and poofed into the Seven Heavens, or been called to Ysgard or The Gray Waste of Hades. They forget or only dimly remember their previous lives, and become closely tied to the plane of their afterlife, which they're generally not allowed to leave. They fuel and become a living part of the plane they inhabit, unable to truly perish. But if they die somewhere else, such as in Sigil, they cannot rejoin their plane and are lost to oblivion.<br/><br/>Because petitioners are a valuable resource to the Outer Planes, and because they tend to be the escaped or stolen property of gods or godlike creatures, the various factions have mixed feelings toward them. It's generally not good to be harboring something that a god wants back.