- The Source of All Evil is an ancient, demonic essence which rules the underworld and is the show's ultimate antagonist. The Source jumps from host to host to continue his evil and is behind most of the evils of the show, whether it be founding academies to break innocents into his minions; enacting genocide on the wizard race; or even using the four horsemen to attempt to destroy the world multiple times. In his appearance in the flesh, he makes multiple attempts to corrupt and mentally break the Charmed Ones and their allies before attempting to use the power-draining Hollow, against the wishes of his minions, despite the fact it would cause him to consume all of existence. Returning from his vanquishment by possessing Cole Turner, the Source corrupts his and Phoebe's unborn child into evil. Returning in the season 9 comics, the Source has his minions murder the innocents saved by the Charmed Ones to revive himself once more, before driving San Francisco insane and trying to wipe out the Charmed Ones once and for all. The evilest demon in existence with a rap sheet that spans millennia, the Source of All Evil truly lives up to his name.
- Barbas, the Demon of Fear, is a ferocious sadist who savors nothing so much as murdering people with their worst fears. With a legion of terrified dead behind him, Barbas was banished from the world and can only return if he kills 13 unmarried witches before the stroke of midnight on the 1,300th anniversary of banishment—Friday the 13th. Murdering multiple witches with fear, Barbas is banished by the Charmed Ones but proves incredibly tenacious. Returning numerous times, Barbas kills countless innocents with his powers and even attempts to take over the underworld to spread the terror further, his final appearance centering on his attempt to even murder kids under the Charmed Ones' protection.
- "The Devil's Music": Masselin is a demonic soul trader who makes deals with mortals in return for them giving him good souls. Masselin then devours them and keeps them alive within himself as he tortures them for pleasure. Signing in band manager Jeff Carlton, Masselin threatens to burn him alive if he doesn't bring him an endless supply of victims, and later adds the Charmed Ones' young friend to his collection to lure them out.
- "Blinded by the Whitelighter": Eames is a sadistic and intelligent Warlock who's been killing witches for their special powers for decades. Acquiring various abilities, Eames makes plans to use them as a way to enter the heavens. Eames then plans to massacre all Whitelighters and then, with their witch charges unguarded, wipe them all out as well in a genocide. Capturing and slowly killing a Whitelighter for her powers, Eames mocks her as she's dying while gloating that her death will mean the end of all that is good thanks to him.
- "Wrestling with Demons": Kellman is the Source's chosen ruler of the demonic academy. A former human, Kellman gleefully sold his soul to become a demon and now tricks and manipulates others into doing the same. Finding troubled athletes, Kellman subjects them to nightmarish training where death awaits failure. For each graduate, the final step into demonhood is the murder of an innocent, often a loved one, as seen when he tries to force Prue's ex-boyfriend Tom into murdering his own mother, with a vast legacy of successful Demons for the Source's army behind him. When bested, Kellman attempts to murder Tom's mother himself out of sheer spite.
- "Size Matters": Gammill, The Collector, was once a handsome man with a fondness for kidnapping women and shrinking them before baking them in special clay to make them into figurines he adds to a macabre collection. Cursed so that his appearance is as hideous as his soul, Gammill uses a golem to lure in other women over the course of decades so he may burn them endlessly in his kiln and fulfill his desire for the greatest collection in the world.
- "Oh My Goddess!" two-parter: Cronus, lord of the Titans, once reigned over the world as a bloody tyrant responsible for countless deaths. Upon being freed, he callously murders one of the only remaining Titans and sets about an attempted extermination of the Elders and Whitelighters. Cronus massacres most of them, trying to hunt down any hiding survivors and kill them along with any who shelter them before returning to terrorize the entire world.
- "Show Ghouls": Count Roget, the owner of the Cabaret Fantome, has the members of his club burned alive as a sacrifice to the demon Sargon. Roget then helps maintain a loop where the members are trapped and forced to have the same fate every day for over a hundred years. When one of his victims escapes and tries to get help, Roget has him captured and instead tricks the Charmed Ones into freeing him so he can now enjoy his freedom at the cost of innocents.
- Mystic Knoll non-canon novel, written by Diana G. Gallagher: Abigail Thornwood is a monstrous teenage sociopath who has tapped into the natural mystical power of her town. Abigail plans to purge anyone who's even slightly offended her—along with their entire families—and to this end, concocts a dark scheme. Magically seducing a man into giving her a child, Abigail warps her child into a monstrous and mindless Jersey Devil, intending to use her to wipe out all her perceived enemies. The painful transformations into the Devil haunts Abigail's daughter and causes her pain, with Abigail herself bodyjacking her daughter to personally take her revenge when she's hindered.