Satan's first "appearance" was in the very first comic, where Riff spammed Satan and summoned him into his computer. This resulted in Riff getting Windows 95 on his Mac, which prompted him to download an archangel to his harddrive as well. Satan and the archangel decided to resolve their differences over a quake deathmatch. Neither Satan nor the archangel Chuck were drawn in the comic, just the backside of the computer monitor. It's later revealed that Riff's spam permanently screwed Satan's computer, and as a result, he now places spammers in the deepest part of Hell.
Satan makes his first visual apperance in K I T T E N, where Mr.Glee describes his appearance "as if the shadows themselves rushed to his side and clung to him like drunk bimbos at one of those new-fangled heavy-metal concerts!". At the following party, Satan took a drunk dare to father a bunch of satanic kittens, later known as THE EVIL.
During the Mohkadun storyline, it is apparently revealed that "Satin" originates from "The Never," a dimensional prison for demons.
A more prominent role is played by Satan in the "Meanwhile, In the Dimension of Pain" half-official storyline (written by Ian McDonald ), where his problems with the demonic women become a central plot point. He is revealed to be the ruler of Hell, and having a harem of several hundred wives. Satan sends out his riders of the apocalypse , but when they are foiled by Deplora's riders of inconvenience , he decides to pay her back by flooding the Dimension of Grief with the grief of email spammers.