The Devil, also known as Lord Dis, the Torturer Inexorable, Satan, Satanas or Lucifer, was defined by Jenny Everywhere as the “symbol of all humankind's evil and depravity”. The Devil was, in most universes where he existed, the greatest of Demons and the ruler of Hell. Some incarnations of Jenny Everywhere occasionally ran into, and opposed, versions of the Devil.
In one universe's Hell, the Devil's exact features where in constant flux. He appeared as a Minotaur-like being, with the head of a fanged calf with an enlarged cranium and small horns. He hovered, wreathed with flames. (COMIC: Jenny Everywhere Vs Hell) In another universe where the Devil was apparently not real, Jenny Everywhere's mental picture of him looked something like Pan, whose physical appearance was that of a man with sharp features, horns and a pointed goatee. (COMIC: Holiday Pandemonium) Reality Z-25 31-H looked somewhat like this picture, minus the goatee; he was in fact completely bald, and also notable for wearing a cape. (COMIC: Hell Is Too Good For Him)
Personality
The Devil as encountered by Jenny was an overly self-assured ruler who belittled mortals and never seemed to consider the notion that they might have a threat to him, have a point against him, or even so much as fail to be awed and terrified by his presence. He was bigoted and spiteful, insisting that girls were “meant to marry nice boys and keep house”. (COMIC: Jenny Everywhere Vs Hell)
In one universe, the Devil ruled Hell from the deepest level of the Underworld. After Jenny Everywhere was pulled into Hell only to refuse to submit to her allotted punishment, she was pulled down to the Devil's throne room, where he attempted to break her spirits. However, a defiant Jenny told her his moralising, misogynistic lectures about the “filth” of homosexuality were no better than the sorts of things her granny had said to her when she was fifteen. She gave the baffled Devil a psychic glimpse of the infinity of her incarnations, which knocked him out. Stepping over his prone body, Jenny announced that Hell was no longer his kingdom and this was “Day One of the Republic of Hell”. (COMIC: Jenny Everywhere Vs Hell)
The Devil personally welcomed Armstrong Fatbuckle, “the Worst Man in the World,” to Hell after he died in a car crash. However, Fatbuckle immediately became an offensive nuisance, causing mayhem, littering, and even sleeping with Mephista. Outraged, the Devil ended up banning Fatbuckle from Hell, returning him to the land of the living as an undead skeleton. Although this was meant to be an ironic punishment — with the skeletal Fatbuckle no longer able to indulge in the pleasures of the flesh he had so enjoyed in life — Fatbuckle quickly adapted to his new existence, finding that he could still party and dance all night long as a skeleton and that, either way, it still beat being damned. (COMIC: Hell Is Too Good For Him)
After Jenkins was killed and his soul ended up in Hell, Kelly got the witches Alicia and Babs to perform a ritual to send her to Hell. There, she was similarly personally welcomed by the Devil, but interrupted his welcoming speech to explain that she was here “on business”, wanting to make a deal to get Jenkins back (not, of course, out of the nonexistent goodness of her heart, but because her superpowers only worked in his presence). The Devil agreed, trying to dramatically announce that she'd have to sell her soul in exchange; to his dismay, she readily agreed to this price, and even quipped that she found it underwhelming that she did not have to sign the contract is blood. Put off by her combined ruthlessness and lack of awe-struck fear, the Devil got the deal over with as quickly as possible and then angrily sprung Kelly and Jenkins back to the mortal plane. (COMIC: Journey Out Of Misery)
Behind the scenes
The Devil is a well-known religious, mythological or folkloric figure, by which token the character can be considered public domain, although the details of specific design used by individual artists and writers may belong to them in some cases.
Open-source elements making up the core Jenny Everywhere mythos