Stingy Jack.
The Jack-O'-Lantern was named after the infamous Irish figure known as Stingy Jack.
Overview[]
Jack-O'-Lanterns, as they are adequately called, are actually reliquaries for the souls of the departed who wander Limbo. These souls are used by Stingy Jack as a means of keeping his lantern alight in order to traverse the uncharted borders beyond Hell itself.
Often times, when a human soul becomes a ghost, they exist on a plane that borders between life and death, and on said plane they come across Jack where he tricks them into becoming reliquaries for his lantern. It is later shown that Jack can also use the souls he harvested for his lantern to fight for him to where they appear as black shrouded apparitions with jack-o'-lanterns for heads that resemble their own.