How comfortable would you be with moving into the old Dark Lord's citadel? Or spending the night in Count Dracula's vacant coffin? Maybe you would you fancy a dip in the old dunking pond where the witch was finally defeated? If you feel that some unspeakable lingering evil will come to claim your soul and send you into damnation if you even think about doing these things then you have the right instincts.
Evil leaves a sticky trail, and even after it's been gone for ages, that trail will have left traces in the places it frequented. A realm, structure, or space that was once evil or had an evil presence within it will always have the possibility of some evil residue lingering just beneath the floorboards. The place may have been repurposed by the forces of good, but make no mistake, there are still tiny dregs of evil left in the bottom of that barrel. The effects of whatever the dregs are may not manifest right away, they may even take centuries to appear, but when they do, whoever is renting out Evil's Old Apartment will find themselves dealing with a far more insidious threat than usual.
The dangers also tend to have a higher mortality rate than whatever the scope of the work is used to dealing with. In extreme cases, the current inhabitants might find themselves facing a pissed-off remnant of the previous occupant.
While the things left behind can be anything between belongings left by the previous evil, to malicious magical remnants lurking in the walls, all of them, without fail, will be extremely well-hidden and easily missed by any initial scan. However, obvious things like garbage or chemicals that the previous occupant didn't properly dispose of may also rear their head as some kind of threat. The most likely places characters will find residue, when it does manifest itself, will be in the basements, attics, and storage spaces of the structure. In cases where the evil residue is not centered around an object or location, it may be present throughout the entire residence in the shape of a curse.
Canny villains can even weaponize the residue by leaving a Fail Safe or Soul Jar in a dusty corner of the building. Not-so-canny villains can just take the option of leaving a malevolent curse that persists after their departure/demise. The most common cause of attacks, however, is people unearthing and tampering with physical remnants of the previous evil.
This trope lends itself more readily to magical settings, but it can also fit into the world of sci-fi through things like failed experiments or viruses in the system. One may try to break the curse or cleanse the evil that has taken root in the place, but such things are never easy (if even possible in some settings), and usually require something extraordinary, such as divine intervention or a World-Healing Wave.
Compare Sealed Evil in a Can (for when a presence is sealed within a place), Leaking Can of Evil (for when the originator of the evil is not directly present but is still is an active part of the threat), and Villainous Legacy (for when the work of a villain lives beyond them). See also Unholy Ground.
Contrast Indian Burial Ground for when a site is actively haunted by a presence.
- In Inuyasha, after the mortally-wounded bandit Onigumo sold his soul and his body to become Naraku, the spot where he formerly lay was left corrupted, and even fifty years later, nothing grows there, even as moss has overrun the rest of the cave.
- Judge Dredd: While hiding out in the Mega-City following Necropolis, Judge Death briefly occupied a room in the Sylvia Plath block managed by the virtually blind and deaf Mrs. Gunderson. After he moved on, his evil presence left a psychic mark on the place, causing a homicide and suicide epidemic that led to virtually the entire block being abandoned.
- The series Red Light Properties is about a psychic who makes his living going to houses with violent pasts and clearing away any ghosts or poltergeists that might have taken root there so that a real-estate agency can more easily sell them.
- Septimus Heap series novel Flyte. The Dark Wizard DomDaniel despite having only occupied the rooms of the Extraordinary Wizard Marcia for a few months leaves behind a nasty taint of black magic that attempts to possesses Marcia when she least expects it.
- Harry Potter: Voldemort leaves behind a pretty nasty Soul Jar during his time at Hogwarts but his left overs are small potatoes next to the nigh demonic Basilisk the founder of the Slytherin House stored in the pipes.
- In the third book of the Graceling Trilogy we discover that the former ruler of Monsea (who was blessed with an astounding ability to make people believe anything he wanted to), left a nasty taint on the kingdom for his daughter to deal with when she assumes the throne. The good old king in addition to being Cursed with Awesome, was a creepy sadist who had a favorite past time was to go a torturin' his subjects with his gifts. The fall out of having literally hundreds of people mentally tortured into believing things, leaves the new ruler with the problem of having the occasional person or two go completely nuts out of the blue. Needless to say, she tires of it real quick.
- This is a big magical law in the Tolkien's Legendarium.
- In The Lord of the Rings, a place contaminated by the forces of evil is forever tainted, even if it was originally built by one of the Free Peoples (one example is Minas Morgul, formerly a Gondorian city of Minas Ithil, which was so tainted by evil that the Gondorians had to destroy it rather than reclaim after Sauron's defeat). Various attempts to reclaim places such as Moria (a former Dwarven underground kingdom) invariably end in tragedy. No one makes an attempt to claim Saruman's tower of Orthanc after the evil wizard is banished: they just surround Orthanc with Ents and Huorns and make sure no one tries to squat in the tower. Only the places that were merely destroyed by Sauron's minions, not claimed as their own, such as Osgiliath and Fornost, are rebuildable and reclaimable.
- It even works if a completely nice structure is built on evil-infested ground. The fortresses built by Gondorians in Mordor to keep Sauron's lackeys from resurging, such as Cirith Ungol and Morannon, eventually withered, became abandoned, and Orcs moved in without any opposition.
- The biggest example of this in Tolkien's writing is when, in The Silmarillion, the whole world is tainted by Morgoth pouring his spirit into it to control it. In the early days the world was as beautiful and perfect as Valinor before Morgoth introduced evil, suffering, and decay. This also affects everyone who lives outside of Valinor, even to the present day.
"The lies that Melkor, the mighty and accursed, Morgoth Bauglir, the Power of Terror and of Hate, sowed in the hearts of Elves and Men are a seed that does not die and cannot be destroyed; and ever and anon it sprouts anew, and will bear dark fruit even unto the latest days."
- A Maybe Magic, Maybe Mundane example is in A Song of Ice and Fire: the castle of Harrenhal was built by a tyrannical king (named Harren), who died right there when a dragon roasted him. Since then, no one manages to hold this castle for long, and everyone thinks of Harrenhal as an unholy and cursed place. The possible rational explanation for that is that the castle is too big for any non-royal feudal lord to properly maintain, and hard to defend properly because of the never-repaired damage caused by the dragon.
- The Wheel of Time Series provides us with the nightmarish hell hole of Shadar Logoth. The city was once a great and heroic city on the side of light but during a long war against the full onslaught of the Shadow - (Analog to the Devil), the city got a new counselor that convinced the people of the city that they had to be as dark and as hard as the Shadow to stand a chance. This attitude led quickly to the city abandoning all its allies to fend for themselves against the shadow and created an air of supreme paranoia within all its residents. The atmosphere of hatred within the city was literally so potent that it seeps into the foundations of the city. Fast Forward a thousand years or so and Shadar Logoth has become an Eldritch Location that serves as the only source of evil within the entire series on par with the Shadow.
- In Dragon Bones castle Hurog is stained by the evil magic that turned the place into a Powered by a Forsaken Child building. This is implied to be the reason why an unusual high number of people don't survive their childhood there, turn mad, or have other things wrong with them. Ciarra, for example, was born mute, with no physical reason to be found. She gets better once the place is de-cursed and she goes to live somewhere else.
- Redwall: Saint Ninian's Church used to be a harmless place until Cluny the Scourge captured it and used it as a headquarters for his assaults on Redwall Abbey. After he was defeated, its former occupants never moved back in, leaving it abandoned and letting other invaders claim it during their attacks. After several generations of being a vermin base, Rollo orders it destroyed because it's become nothing but a home for evil.
- The Canterville Ghost: The bloodstain on the carpet started out as Rustproof Blood from the murdered Lady du Canterville, however, Mr. Otis cleaned it up. Simon du Canterville, the titular spectre, won't have it and keeps replacing it. By using Virginia Otis's oil paints.
- H. P. Lovecraft fiction:
- The Blasted Heath in "The Colour Out of Space" is either this or Leaking Can of Evil.
- Exham Priory in "The Rats in the Walls", and specifically the dark cavernous realm under it, where rampant cannibalism was practiced, drove the descendant of the family mad and caused him to revert to his ancestors' murderous habits.
- Deep Space Nine. A Cardassian computer program that the Federation accidentally triggers tries to kill every one aboard the station in increasingly severe attempts.
- Buffy the Vampire Slayer. A children's home turned college dorm, called the Lowell house is tainted by the lingering psychic mojo of the sexually abused children that once lived there. The mojo manifests itself as a gang of poltergeists that heighten and live vicariously through various college students' steamy err... interactions.
- Doctor Who: In "Ghost Light", the events of the episode left a psychic trace in the house strong enough to terrify the 13-year-old Ace when she broke in a hundred years later.
- Warhammer 40,000:
- Just about anything corrupted by Chaos becomes this, often the only way to remove it is to destroy the planet.
- A variation with the Orks: a planet that's been invaded once will pretty much always have them, since the way they reproduce is by releasing spores on death that float around and eventually mature into even more Orks (these will either join an Ork warband or horde or, if none are available, become Feral Orks, which have a lower level of technology than the regular kind), though using fire to dispose of their corpses helps a bit. Having a completely infertile world (Forge and Hive worlds usually quickly become such) helps a lot more. Interestingly, one of the Aeldari Craftworlds actually found a way to remove the spores using reconditioned anti-gravity farming vehicles, but they hate humans so much that they aren't sharing.
- Deadlands offers a metaphysical mechanism of this trope working. In this universe, an evil place is feared by people, and things feared by people become evil because of Clap Your Hands If You Believe. So, any villain who lives in a town or house long enough to give it a frightening reputation, automatically stains his real estate and makes it evil-infested.
- Dungeons & Dragons has variant rules for DMs wanting to create settings where the taint of evil is a very real threat.
- Magic: The Gathering has several examples, the most triumphant one most likely being Urborg, Tomb of Yawgmoth. A legendary land that represents the final burial place of a Deader Than Dead Big Bad of most of the game's early history, simply playing Urborg turns every single land in the game into a Black Magic-powering swamp.
- The Shadowlands in Legend of the Five Rings are the site of a dark god's fall and the area his taint has covered. Held at bay by the Crab Clan and the Carpenter's Wall.
- Princess: The Hopeful: Any place where an act of great evil was committed can become tainted by the Darkness, weakening those with good intentions and corrupting the souls of anyone who spends too long or experiences emotional stress within its boundaries. Fortunately, Taint can be cleansed, either by physically destroying the Tainted Place or by performing deeds of goodness and hope to oppose its corruption.
- Mega Man ZX: Areas M and N were the crash site of the space station Ragnarok, with which Mega Man Zero's Big Bad Dr. Weil fused himself long ago and where Model W's malevolent energies have been seeping into ever since. Said area is full of strange phenomena, including the appearance of Reploids there who should've died long ago.
- World of Warcraft: Pandaria is a continent wide example of this phenomenon. Although it looks charming, Pandaria is infested with the disturbingly powerful remnants of an exceedingly nasty Old One known as Y'Shaarj. Although he was defeated by the Titans long ago, Y'Shaarj cursed the land with his dying breath to be forever riddled with shadows of "his former self". The curse is thought to be behind the shadowy emotion eaters known as the Sha, as well as other mysterious phenomena that plague the island.
- The Blight from Dragon Age corrupts everything it touches. Even after the Archdemon is dead the lands the Darkspawn ravaged never fully recover as a result of the corrupting effects.
- BlazBlue: in the backstory, the Black Beast ravaged the world while leaving seithr, Toxic Phlebotinum that pollutes the ground and waters, and can cause deterioration of the human body and mind. After the battle against the beast (called the Dark War) is over, most of the world in the lower elevations (including the seas) have been covered in seithr, forcing the survivors to build cities in high mountains to avoid them.
- Terraria: The Corruption, Crimson, and Hallow biomes which infect 'pure' biomes such as a forest, desert, or jungle. The former two spawn Eldritch Abominations, while the last biome is a Crapsaccharine World. Before beating the Disc-One Final Boss, these biomes can only spread across dirt, but afterwards, they spread much more aggressively, being easily able to corrupt half of the overworld before the defeat of another boss slows the spreading of these biomes.
- Doom: If the statement that "the Demons have brought their own reality with them" in Doom II's story text is anything to go by, being tainted by evil is why none of the canon levels from the Doom series' 2D graphics era to be set in the land of the living look at all recognizably or convincingly like a real-life example of the type of location the level name suggests it is supposed to be.
- The Suffering and its sequel are set in locations where the atrocities of the past have left a supernatural imprint on the land, eventually resulting in manifestations of hideous beings modeled upon the violence and corruption that took place there, from Carnate Island's executions to Charm City's urban decay. Worse still, it's implied that this isn't abnormal, not even in the case of the island: any location in the world that's seen enough bloodshed and torment can manifest this phenomena - all it needs is the right catalyst.
- The ultimate evil Overlord from Ninjago was defeated by the heroes in the middle of a crowded city in a major "final" battle that apparently destroyed the Overlord forever and created a clearing about the size of a small park. Following a Time Skip of a few years they come back to this site and discover that Cyrus Borg, an eccentric tech genius, has built a sky scraper right on top of the clearing. Through this fine fellow's Genre Blindness a remnant of the ultimate evil becomes a virus in the network of his systems.
- Played With in The Simpsons when Marge sells a murder house to her neighbors without explaining the history of the property. Of course, Marge feels guilty about this soon after the transaction, and she decides to offer them their deposit back the next time she meets with them. When she finally goes to explain and apologize about the omission she discovers that they aren't angry at her about it and are in fact delighted with the house's history. The most troubling part about it is, the neighbors exhibit a bus load of horror movie tics during the conversation. Marge and the audience can't tell if they're just joking or if an actual remnant of evil exists within the property.
- Urban legends about St. Petersburg in Russia portray it as "a city built on bones", referring to the fact that it was built by forced serf labor and many builders died during construction, and to the city's founder Peter the Great's general cruelty (and that's not even touching the German siege in World War II, when it was called Leningrad). In these legends, St. Pete is usually the place where something mysterious, gothic and fearsome happens.
- This is sometimes the reasoning behind lowering the prices of houses where people have died in. People do not like places where people have died, even those that don't believe in ghosts. The belief that death might leave some sort of mark on a place, if not an outright haunting, has driven off many a customer from an old house.
- Sandy Hook Elementary, where an infamous shooting occurred in December 2012, was torn down for this reason.