Clay cannot be turned to gold. Without magic, you're just a human.
~ The Witch Queen to the 37th Dolan.
How 'bout a little Magitek mayhem?
~ Kefka Palazzo's famous catchphrase.
Villains who utilize magical powers and/or skills. These evildoers have various monikers which include Casters, Conjurers (sometimes spelled "Conjurors"), Enchanters, Enchantresses, Illusionists, Magicians, Occultists, Spellcasters, Warlocks, Witches, and Wizards. However, it must be noted that how these villains gained or utilized the magic varies:
Wizards/Witches/Warlocks: These villains gain the ability to use magic mostly through extensive studies on magical writings and spell books. While any spell will do to prepare for their acts of villainy, in the cases of Warlocks and some Witches, they prefer dark or demonic magic as their primary power of choice.
Sorcerers/Sorceresses: These evildoers mostly have the innate talent for magic rather than studied, meaning they already have mastered some spells prior to their sorcery-related educations. An example would be Lord Voldemort who, just like his nemesis Harry Potter, mastered his innate magical powers to a small degree when he was young.
Illusionists: A type of villain who can create realistic illusions. Unlike magic-users or reality-warpers, these illusions are not actually real but, to their victim, they can be frighteningly realistic. Many illusionists love to make their victims believe these illusions are real in order to trick them or simply mess with their minds. Sometimes, though, an illusionist's real goal is to simply live in a fantasy world where he or she is happiest but become villains to keep their fantasy world alive, such as Ray Thompson who only wanted to recreate the world he once knew but imprisoned all the survivors of a nuclear war to make sure it stayed the way he wanted it to.
Enchanters/Enchantress: These villains' magical power of choice is rendering something or someone under a spell.
Alchemists: Villains who use the mystical science of Alchemy for their criminal goals. Alchemy differs from story to story, but it most often focuses on transmuting matter to turn it into something purer (the most common example being turning any metal into gold) and making oneself evolve through meditation and experiments (in most stories, this evolution is about becoming immortal). In some stories focusing about magic and sorcerers, (Harry Potter, for instance) Alchemy is described as a special brand of magic; thus, most of its practitioners are sorcerers.
Emotion Vampires: Through mystical means, some villains can channel specific emotions (though they prefer negative ones such as fear, hatred and disgust) to increase their powers, be it from their own emotion or of those around them. An example of this would be The Sorcerer, whose powers would be amplified should everything around him be in a chaotic state.
Pseudoscientists/Unconventional Scientists: Villains with powers, abilities, energies, or concepts that, within their respective worlds/universes, and they are regarded as a science or even commonplace, despite the fact that they are abilities that are unnatural or even supernatural in the eyes of the audience. Some of these works illustrate a clear difference between said abilities and magic, but for the purposes of this wiki and the sake of simplicity, should be regarded as magic. Examples of this include ki from the Dragon Ball franchise, bending from Avatar: The Last Airbender, Semblance and Aura from RWBY, jutsu from Naruto, the Force from the Star Wars franchise, and certain types of the aforementioned alchemy, such as in Fullmetal Alchemist.