Characters, groups or creatures related to Satanism, the worship of Satan, the most powerful and evil fallen angel after his rebellion towards God in Abrahamic lore, particularly Christianity.

Satanists are usually extremely dangerous individuals who are incited to utilise heinous methods, such as murder and rape, to worship Satan. Human characters associated with Satanism are often extremely deranged individuals who try to summon him, gain demonic powers, demonise communities especially religious communities, or, in the worst of cases, unleash the apocalypse, and few of these characters may succeed. Most are either possessed/brainwashed by the Devil or fanatical followers of Satanism. Non-human characters, on the other hand, are often malevolent spiritual beings or beastly creatures with direct linkage to the Devil himself or embodiments of him, whether physically or symbolically.

Because of this, Satanism is considered the most sinister branch of dark magic, and in some cases, the most sinister religion, though it is often exaggerated as, in reality, Satan is given limited power by God to do direct harm towards humanity; though he is able to drive, influence or possess humans to do evil and mainstream society's overall contempt for Satanism.

Satanism is similar to Voodoo.

Modern Satanism is divided between those who practice it as a philosophy and those who claim to follow it as a form of religion, fiction almost exclusively deals with Theistic Satanism (or "Devil-Worship" as it is often known to the mass public) - though in reality most portrayals of theistic Satanism in fiction is more akin to Chaos Magick, thus to qualify a villain must specifically invoke "Hell" or "demons", preferably Satan itself, otherwise they are best left under "Magic".

In many settings a Satanic wizard or sorcerer is known as a Warlock, while a Satanic witch is known as a Beldam.