Uncle Lewis Vendredi made a pact with the Devil himself to spread evil throughout the world. Responsible for the events of the series, Lewis locates and acquired multiple old items before he would personally curse them and distribute them, often in ways that showed a sadistic edge and made it so they would always result in death and chaos to gain hell more souls. When Lewis realized his pact with Satan was resulting in his immortal body aging too much, he tried to break the deal, resulting in his own death at Satan's hands. Returning as a ghost, Lewis attempts to return to life and murder his family members who are trying to regain the cursed objects so they can do no more harm. Eventually, Lewis tries to get back in Satan's good graces by opening the very gates of hell and allowing Satan access to Earth to consume or torture all of mankind.
Winston Knight, from season 1's "Double Exposure'', is an ambitious news anchor who uses a cursed camera to make a duplicate of himself that he must destroy within five hours by destroying the negative print. Winston, to boost his ratings, sends his duplicate out to murder women with a machete so he can cover the murders and portray himself as a hero, killing at least ten innocents with no sign of stopping. When the hero Ryan's girlfriend Cathy catches Knight with his duplicate, Knight makes her a victim as well. Realizing Knight is guilty, Ryan snatches the negative print, meaning Knight risks death if the five hours lapse. When the group offers a trade, Knight attacks their friend and mentor Jack and creates a double of him, intending to have the double murder Ryan and his cousin Micki so he can frame Jack as the murderer and continue his own rise into stardom.
Horst Mueller and Oberst Rausch (alias Karl Steiner), from season 2's "The Butcher", are a pair of Nazi war criminals. During the war, Rausch, known as "The Butcher", was an infamous torturer and murderer who met his death at the hands of Jack Marshak. Mueller, using the occult, revived Rausch and despite being imprisoned as a war criminal, directs Rausch to murder the former members of Jack's squad using his signature barbed wire as a strangulation device. Promoting fascist and bigoted ideals as a radio host, Rausch mentally torments Jack and the other survivors while he prepares to murder them. When confronted, Mueller declares their ultimate objective is for Rausch to enter politics and eventually bring about a rebirth of the Nazi regime, both believing they are the Master Race, destined to rise anew.
Asteroth, from the two-part season 3 premier "The Prophecies", is a Fallen Angel and priest of Satan who is devoted to freeing his lord and master. Attempting to fulfill dark prophecies, Asteroth aims to kill a pure-hearted nun, first by infecting the minds of other nuns to drive them homicidal before they die, then driving the animals of the village murderously insane. When this fails, Asteroth brainwashes Ryan and has him murder the nun, before having him abduct a crippled girl with unshakeable faith in God so Asteroth can sacrifice her to Satan and have his master manifest in her body as The Antichrist. When he confronts Jack on his motivations, Asteroth gleefully reveals his future vision of the world, showing Jack images of mass destruction, death and oppression on a global scale. Intending to end the entire world, Asteroth is without doubt one of the cruelest monsters ever faced by Ryan and Micki.
Alex Dent, from season 3's "Mightier Than the Sword", is a Serial Killer posing as a true crime author. Dent uses his magic pen to turn unwitting victims into serial killers, targeting whoever Dent chooses. He disposes of them by bringing them to justice for crimes they can't remember committing. Dent is introduced using this power on Clint Fletcher, whom he used to kidnap and murder 18 women. Dent sadistically reveals to Fletcher that he is about to be executed for Dent's own crimes, and enjoys watching him die. At a writers' talk, Dent taunts Clint's enraged brother Jerry just to revel in his own emotional cruelty. Dent then uses his pen on the priest who oversaw Fletcher's execution and uses him to tie up loose ends. He murders Jerry and a detective who grew suspicious of him, before leaving the priest amnesiac and ruining his life. He captures Micki and has her target his ex-wife Marion, who is attempting to blackmail him. He plans on making her death the worst he's ever done purely for her slight against him, and comes along to watch her murder personally. When Marion fights back, Dent throws her down the stairs to try and cripple her, so that she will be paralyzed and conscious as she is carved up.
Two undeniable ones for Micki occur in "Dr. Jack" where she electrocutes the villain with a defibrillator and "Bedazzled" where she uses a mirror to reflect the burning light of the lantern back at its owner. She's overall clever and resourceful throughout the latter unusual Hostage Situation episode, whether in feigning ignorance, stalling for time while looking for the entrance to the vault (twice!), lying in wait to hit the villain over the head as soon as he opened the vault again, arranging to shock the villain by wrapping exposed lamp wires around the lantern, and having Richie throw it over the railing to make the villain fall.
Ryan's would have to be: using the jumper cables to ground the villain's charge in "The Electrocutioner" so he electrocuted himself through the radiator pipes; knocking Reverend Josiah out the window by letting go of the Quilt of Hathor; tricking the villain of "Tails I Live, Heads You Die" into bringing Micki Back from the Dead; getting the cursed pocket watch from "13 O'Clock" away from Reatha right as the clock reached one; and strangling the werewolf from "Scarlet Cinema" with silver-nitrate-coated movie film.
As for Jack: tricking Lady Di out of the cup in "A Cup of Time"; going apeshit on the villain of "Brain Drain" after he used the trephanator on his Old Flame; refusing Uncle Lewis's Final Temptation in "Bottle of Dreams" so as to save Micki and Ryan; and setting up a small weapons arsenal to use against "The Butcher", then taking him out with his own barbed wire after removing the Thule Amulet (after he had taken out all of Jack's Band of Brothers).
One cursed object, a compact, appears in two episodes ("Vanity's Mirror", then "Face of Evil") with different powers each time. The compact changing its powers seems to make no sense at first, until one considers what happened in "Vanity's Mirror"—not only did its owner end up killing herself once she achieved the love she wanted (but which she knew was only compelled and thus not truly hers), but she herself was a lonely and rejected girl whom everyone in her school believed unattractive. Killing herself after achieving her "love" instead of killing the man in question would break the love compulsion curse, and at the same time the death of an "ugly" tragic girl would cast a new curse related to giving beauty and the chance to have a life others would envy.
At first the name given to the "Quilt of Hathor" is rather inexplicable, since an item marked with a Satanic pentacle and used to frighten people to death seems to have nothing to do with either the Egyptian pantheon or specifically a deity of goodness, love, motherhood, and community. (Although in and of itself a quilt would fit those last two.) But the main villain of the episode tends to use the quilt to kill people while envisioning herself as a sensuous, lusty woman at parties and dances, something which Hathor does hold sway over...and Hathor is also a goddess of fate who was believed to inspire people through divinatory dreams.
Why did the victims in "Symphony in B#" just stand there and wait to get stabbed? Look at their faces when Korda "plays" the violin. Of course a secondary ability of the violin would be to hypnotize its victims — it'd help greatly in its ability to kill.
"Mesmer's Bauble", wherein the pop star the episode revolves around dies by being melted into the villain, is hard enough to watch after learning her actress, the real-life singer Vanity, nearly died from renal failure due to drug overdosing and thus dropped out of show business. (In the episode her character loses her manager and lover, and nearly breaks down saying she can't go on...) It gets worse learning she died in 2016, right before her ex-partner and music mentor, Prince, died as well (eerily, at the same age). To cap it off, her character also sings a cover of "Nature Boy" in the episode—a song quite fitting for a story about a fan with unrequited love, but which was also used in Moulin Rouge!, wherein the singer character also died onstage.
Jack's Together in Death line at the end of "Brain Drain" is a little hard to listen to and watch after Vi's actress Carrie Snodgress' death in 2004 and Jack's actor Chris Wiggins' death in 2017.
Jack: Well, Vi, now you know if there's anything after. Wait a while, darling...maybe we can be together again...after all...
At the beginning of "The Voodoo Mambo", the estate handler and the realtor seem just a bit too smug at kicking out the Villain of the Week from the home of his late father.
The doctors mocking White Cloud for his Native American heritage in "The Shaman's Apprentice" most definitely seem to be receiving some well-deserved karma when he kills them to cure terminal patients. The chief surgeon coming to report to him that he has told the medical board to revoke his license is even more of an Asshole Victim, to the point that Micki actually thinks they should let White Cloud kill him if it will save her ill friend; her friend being left instead to face the definite likelihood of death in a couple months actually seems crueler by comparison, to the point of seeming like Black and Gray or even Gray and Grey Morality.