SpongeBob SquarePants: Sure! It's the beady red eyes that are a dead giveaway for the evil fellows.
An easy way to tell a villainous (or sinister) character apart from the protagonists, other than giving them a Red Right Hand, is making their eyes red. If they don't start out evil, there's a chance they become so over time or perform full-blown Face–Heel Turn. It's not the same thing as the "red eye" phenomenon in photos, but if cameras could detect evil, or danger these would be the first people they'd catch.
Even those who aren't truly evil or dangerous are often thought to be so by characters In-Universe.
In the progressive algorithm of "Uh-Oh" Eyes we have:
Those with glowing red eyes are almost without exception thoroughly evil or, at least, on a Roaring Rampage of Revenge or filled with Unstoppable Rage. The "almost" section goes to those whose red eyes serve as a marker for their Elemental Powers, since Fire Is Red typically or they’re Playing with Fire. Albino characters with red eyes may suffer from this association with evil; see Albinos Are Freaks.
If the character can control others and brings their red eye color with them, it may then overlap with Eye-Dentity Giveaway.
Not to be confused with being worried about a late-night airline flight (which would probably fall under Plane Awful Flight), or with the film Red Eye (which is about such a flight), or with the liquor. Sometimes a part of Burning with Anger, and thus a harbinger of wrath from the Seven Deadly Sins wrath.
It should be noted that this trope is NOT just for characters who have eyes of this color, but when the color actually indicates the character is evil or dangerous, or has the Face of a Thug because of their eye color. Please do not add characters who just happen to have eyes of this color without the proper reason behind it.
- Anime & Manga
- Comic Books
- Films — Live-Action
- Live-Action TV
- Tabletop Games
- Video Games
- Western Animation
- When BoBoiBoy Lightning is brought to his Rage Breaking Point, he unlocks his Next Tier Power-Up, BoBoiBoy Thunderstorm, who casts a sudden, piercing red glare upon the villains when he's brought out. Thunderstorm is easily one of BoBoiBoy's most fearsome forms, with his sheer speed, power and ruthlessness.
- Season 2 introduces Fang as the main cast's relatively new classmate, who has red eyes and glasses which appear to have a red glowing tint in the dark. He's aloof, arrogant and has a power band like each of the main characters, and the one who provides such power sources, Ochobot, faints at the sight of him. This makes the heroes wary of him, and it doesn't help that Fang sees BoBoiBoy as an obstacle to his quest for popularity, which has led him to team up with the heroes' enemies at times. It's subverted later on, however, as he eventually befriends the heroes and proves to be well-meaning. However, his red eyes do foreshadow that he's not exactly human.
- BoBoiBoy Fire has crimson irises with yellow rings (and sometimes he has Fireball Eyeballs), and he tends to be a violent Mood-Swinger who is very destructive when angry.
- Boonie Bears: In Season 2 episode 10, those who are within hearing range of the magic flute when it's played on the sun setting become violently aggressive, with their eyes turning red to indicate this.
- Happy Heroes: In the last episode of Season 8, Huo Haha's pupils turn red when he finally has all of Xiao Haha's magic staffs and becomes much more powerful with them.
- In the Lamput episode "Signs", when the police officer has finally had enough of Fat Doc and Slim Doc disregarding the "no [whatever]" signs they come across one too many times, his eyes turn red.
- In Pleasant Goat and Big Big Wolf: Joys of Seasons episode 6, Tibbie's eyes turn red when she gets angry at Weslie, Paddi, and Sparky for accidentally covering her in fire extinguisher foam.
- In the Simple Samosa episode "Sumo Momo", when Samosa is fighting Sumo Momo and finally snaps from him breaking the tip on his head, his pupils go red as he gives him a No-Holds-Barred Beatdown.
- These aren't a constant for any character in Candorville, but most vampires can activate and deactivate them at will. The only exception so far is Saxon, who gets Milky White Eyes either because of his Dhampyr status or because he's a Friendly Neighborhood Vampire.
- The art style usually doesn't allow for eye colors at all, but the infamous "abandoned house" sequence (beginning here) has a close-up of one of Garfield's eyes in the final strip, red like blood, with the pupil contorted into a spiral as he refuses to accept what he sees.
- In another very early strip around Halloween, Garfield explains that around that time cats become bewitched. His eyes began to turn red among other things... that is until he saw himself in the mirror, screamed turned white and passed out.
- Al Capp's Li'l Abner strip had the Nogoodniks, which were the evil version of the Shmoos. They were a sickly shade of green and had "li'l red eyes". They devoured "good" Shmoos, were the sworn enemies of "hoomanity," and wreaked havoc on Dogpatch.
- Fan Vids and fanart that present Elsa from Frozen as evil or generally violent very frequently give her red eyes, rather than her normal Icy Blue Eyes. Glowing Eyes of Doom are a common alternative but red eyes are used more.
Individual FicsAnimal Crossing
- The Terrible Secret of Animal Crossing: This Dark Fic has a few pictures of Tom Nook with these eyes. Really quite freaky.
- Chasing the Moon: Kurosaki Yuzu is a Martial Pacifist, and an absolute sweetheart. That doesn't stop her final bankai technique from giving her these. It's supposed to represent the way a lunar eclipse causes a Bad Moon Rising blood moon. Beware the Nice Ones
- Calvin & Hobbes: The Series: Parodied; the Mirror Universe equivalents of Calvin and Hobbes only have red eyes because they got soap in them while showering.
Sebboh: It's still burning.
- The Bridge:
- When we get our first image of Monster X, the only thing visible under the cloak he's wearing in his glowing red eyes partially subverted as he's a Noble Demon.
- Aria Blaze absorbs some of Kaizer Ghidorah's energy and gains some of his powers. When she uses them, her normally violet eyes turn red, plus she becomes a lot more aggressive.
- The Butcher Bird (One Piece & Tokyo Ghoul): Any ghoul falls into this category, and their appearance usually means a bad day for any Marines in the vicinity.
- Child of the Storm:
- Gravemoss has these to go along with being an albino, and is one of the vilest characters in the setting.
- It's also a sign that the character in question is possessed by the Elder God Chthon.
- Doctor Sinister, a member of Names to Run Away from Really Fast, has red eyes.
- FateBuild: The Mechanical Magus (Fate/stay night & Kamen Rider Build): In chapter 7, Rin's eyes slowly turn red when Shirou tells her what Shinji has been doing to Sakura since Rape Is a Special Kind of Evil.
- The Night Unfurls: The Dreaded Anti-Hero Kyril is a hunter, a killer, an inhumanly fast and strong entity that constantly exudes Killing Intent, even when he's not holding his serrated cleaver. His originally-dark eyes turn crimson when he wants to visibly show others that he's deadly serious. The remastered version switches his eye colour to permanently claret red, like spilled blood, just to amplify the sinister vibe.
Narration from the remastered version: His red eyes were dull, and yet they held a cruel light to them that shone with warning against all sentient life.
- Children of an Elder God (Cthulhu Mythos & Neon Genesis Evangelion): When Rei got jealous in chapter 4, her red eyes glowed for a split-second. Touji and Kensuke were utterly scared out of their wits when they saw it.
"Rei was staring at Asuka, intensely, her face twisted in anger. Her fists were clenched, shaking slightly. It was hard to tell in the sunlight, but they thought they saw her blood red eyes glow brightly for a moment."
"Ohshit," whispered Touji. "She's mad."
- Robb Returns: Eddard's and Jon's eyes become red when they are possessed by their ancestors or the Old Gods. Fortunately, their intentions are benign.
- After his possession, several characters note Eddard's eyes turn fire red at certain moments of importance.
- Brynden Tully and Brienne of Tarth note this in each other after their vision.
- Abraxas (Hrodvitnon): Monster X. The San half of them already has a red eye color, being formerly one of Ghidorah's heads, but when San or the Vivienne half or both of them are sufficiently pissed off, they exhibit Glowing Eyes of Doom which match their "Yellow Lightning, Blue Lightning" red lightning powers.
- Queen of All Oni: Jade gets red eyes when she returns to her Queen of the Shadowkhan persona.
- A Different Lesson: The fic uses this to signify a character falling under More than Mind Control...assuming the reader hasn't figured it out by the time the eyes show up.
- The Boy Who Cried Idiot: A pair of red eyes are the last thing Lincoln sees in his nightmare.
- The Nightmare House: Lucy has a nightmare about dancers with blue eyes that turn red when they're angry.
- What You Wish For: A possessed Carol Pingrey from Lori's nightmare has red eyes.
- Loved and Lost: One of the main antagonists, The Brute Commander Hildread, has dark red eyes, and she's a sadistic Knight Templar.
- Advice and Trust: When Zeruel is about to striking Shinji and Asuka, Rei's eyes start glowing red. That -together with her growling- was the first sign that she was going berserker. Zeruel got his posterior handed to him by Rei herself shortly after.
- Guys Being Dudes: As in the source material, Team GO Rocket's Shadow Pokemon have these. Arlo also does. It's ambiguous why, but it's implied it may have been due to exposure to corrupted XM while creating the Shadow Pokemon.
- A Pikachu in Love: This is the first thing Pikachu and Pichi see after accidentally crashing into an Ursaring's den...
- Pokémon Strangled Red: Steven's eyes turn red after he uses Missingno, and he murders his own brother afterward.
- Discussed in The Utonium Trials when Buttercup overhears others call her red eyed sister Blossom "demon-eyed". Blossom isn't an example herself because she's heroic.
- In Puella Magi Yuuko Magica, Madoka's eyes shift to a shade of red when she's reaching Let's Get Dangerous!.
- In SilfofinaDragon's Sengoku Basara fanfics, Date Masamune and Sanada Mister Seahorse Yukimura's son Masa's Split Personality Sei has blood red eyes. And in misakiyu's illustrations, they are literally colored Splash of Color red.
- Shadamy Comic: When it's revealed that Infinite is pretending to be Sonic, "Sonic" gains glowing red eyes.
- Sonic.exe: The evil version of Sonic first glimpsed on the title screen has pitch-black irises and "two glowing red dots" for pupils.
- We Can Be Heroes: Val Kazkani is an albino alien mobster who regularly terrorizes and bullies the citizens of Krapton, and a boorish thug towards everyone outside his immediate family. The narrative draws a lot of attention to his blood-red eyes, and his youngest sister Su mentions to Lapis that his parents were hoping to exploit the genetic quirks afforded to him as an albino to make him scarier to the people he extorts.
- The Body of the War-Feeder: In this Doctor Who fanfiction, the titular War-Feeder has red eyes. This also happens to the bodies he possesses.
- Ace Combat: The Equestrian War has Red Cyclone, whose eyes sometimes give out a spark or two when he devises a plan.
- In the webcomic adaptation of Christian Humber Reloaded, the sociopathic mass-murdering protagonist has red eyes.
- Dungeon Keeper Ami features this prominently. Keepers all have red, glowing eyes due to the dark magic of their Dungeon Hearts, and they glow brighter when feeling strong emotions, such as anger. This actually becomes a plot point once Ami makes contact with her own world, and is the basis of Tiger's rather Dude, Not Funny! annoying prank.
- Evangelion 303: In chapter 17, when Asuka finds out that her best friend's fiancé has kind of cheated on her, her blue eyes glow red for a moment to heighten she is furious... and dangerous.
- The Good Hunter: The Hunter, being a highly capable killer with inhuman strength, has the deep crimson eyes to match.
- Heart of Ashes: Ancalagon the Black's eyes are described as being coloured like the inside of a volcano when he appears in Kathryn's vision.
- Kid Icarus Uprising 2: Hades Revenge describes Mao Zedong as gaining one when he uses his Code Geass Communism Geass.
- Heirverse: Aizen finds Gin's red eyes beautiful but that may very well be because they imply danger.
- My Immortal: Averted and played straight with different characters. Vampires Ebony and Draco either have red eyes or wear red contacts, and are the Designated Hero good guys. Played straight in that Voldemort (also known as Vlodemort, Vloxemort and other variations), the Big Bad of the story, is frequently described as having red eyes.
- Scoob and Shag: Unlike other characters' white effects, Number One's eyes and Magical Eye Streamers glow red when he uses his powers. The glow from his eyes is strong enough to actually light up parts of the scene in episode #74. The fact that his eyes are a consistent color serves as both a signifier of how much danger he poses to the others and as a hint at how much his Ballyhoo energy has corrupted him.
- In the Cinderjuice story "Sleeping Beetle", Arc Villain Vasile is described as having "malevolent red eyes." Vasile, a member of the Our Vampires Are Different strigoi mort, which, according to vampiric lore do have red eyes.
- In the Warcraft fanfic Tales of a Warrior, the lead, Keleria, who is already a berserker, develops these whenever she slips into blood rages.
- Thousand Shinji: During SEELE's final attack, Shinji's eyes sometimes glowed red when he got really, murderously angry.
- In The New Adventures of Invader Zim, the sclera of Our Vampires Are Different member Norlock's eyes are blood red, highlighting his Black Eyes of Evil pupils and irises.
- Averted in the Monster Musume fanfic Daily Odd Life with Monster Girls - Naki the zombie has red eyes, but is very good-natured and mischievous.
- The Fabrication Machine and all its robot minions from 9 have red mechanical eyes and are hostile to the stitchpunks.
- In Care Bears Movie II: A New Generation, Dark Heart is Colour-Coded for Your Convenience with red eyes, Evil Redhead hair, and clothes in his human form. When his eyes change color, it clues everyone in that his Heel–Face Turn let him Become a Real Boy.
- Darla Dimple in Cats Don't Dance has eyes that flash red when she's feeling particularly insane.
- Disney Animated Canon:
- Mrs. Jumbo from Dumbo normally has blue eyes like her son, but they turn red during the scene where she loses her temper and lashes out at the children making fun of Dumbo, resulting in her being tied up by several circus workers and subsequently being dragged away to be locked up in solitary confinement as punishment for being a "mad elephant".
- Fun and Fancy Free: During "Mickey and the Beanstalk", Donald's eyes turn red when he starts to go mad with hunger. Later, when Willie the Giant wakes up from his nap to catch Mickey, Donald, and Goofy making off with the singing harp, his blue eyes briefly flash red before he gives chase.
- In the Pecos Bill segment of Melody Time, as Slue-Foot Sue tries to ride Bill's horse Widowmaker, who is jealous of Sue, his eyes turn red as he is Horsing Around giving her a ride she will never forget.
- The Adventures of Ichabod and Mr. Toad. As he pursues Ichabod Crane, the evil supernatural Headless Horseman rides a diabolical steed with red eyes.
- Pongo and Perdita from 101 Dalmatians when they are fighting Bumbling Henchmen Duo Horace and Jasper in Hell Hall. Cruella De Vil's Nightmare Face in her final attempt to kill the puppies also counts.
- The Bears Are Bad News bear in The Fox and the Hound has these kinds of eyes, as does Tod moments earlier when he confronts Copper and snarls viciously at him.
- In The Black Cauldron, the Horned King's eyes go angrily crimson after his army of undead warriors has been halted.
- Fidget, when he breaks through the window◊ in the beginning of The Great Mouse Detective, has Red Eyes. Big Bad Ratigan also qualifies◊ during the climax of the film, after his Villainous Breakdown.
- In The Little Mermaid, when discovering that Ariel had failed to turn up for her debut in the concert, King Triton growls out her name in extreme fury while his eyes turn to a bloody shade of red.
- Aladdin. While Aladdin and the Genie are in the cave, Aladdin taunts the Genie about the limitations on his wish granting abilities to trick him into getting everyone out of the cave without using up a wish. When the Genie gets angry and starts giving a speech, his eyes turn red momentarily.
- In Treasure Planet, Silver's cybernetic eye is usually a yellowy-amber-orange-ish colour, but it changes to red when he gets angry/displeased.
- In Big Hero 6, when Hiro finds out that Callaghan caused the death of his brother and apparently has no remorse for it, he removes Baymax's caregiver memory card and leaves him with only the combat information, rendering him a remorseless attacker perfectly capable of killing without hesitation, his eyes glowing red.
- Heavy Metal:
- "Den". The evil queen's eyes flash red for a moment when one of her underlings criticizes her having sex with a prisoner.
- "Taarna". The giant rats that the Barbarian Leader has as his Right Hand Cats have bright red eyes.
- Heidi's Song: All the evil You Dirty Rat! rats have red eyes. Even lampshaded in their Villain Song:
"And 'E' is for your evil eyes of red!
- The victims of Klaus' possessions in Hold Your Breath sport glowing red eyes.
- In Hotel Transylvania 3: Summer Vacation, when Abraham Van Helsing uses his music to control the Kraken, its Mind-Control Eyes burn bright red.
- Ice Age 3: Dawn of the Dinosaurs
- Rudy the Baryonyx, although this is more from albinism.
- The gang of pterosaurs that prey on the possums have them during their chase scene, although the color is most visible when one guy gets himself blown up into a living balloon from a gas berry. Unable to handle the immense amount of gas being released in his body or cheeks, his eyes get filled with the excess, forcing them out of their sockets and inflating into two large balloons. With two giant balloons for eyeballs bulging out from his beak, the red color of his eyes are shown.
- The Iron Giant: When the titular Iron Giant's eyes turn red, it's a good idea to remove yourself from the area.
- Lord Shen, the Big Bad of Kung Fu Panda 2, has red eyes, due to him being an albino peacock.
- Nyra's eyes in Legend Of The Guardians The Owls Of Ga Hoole glow red when she's angry.
- A majority of the Outsiders from The Lion King II: Simba's Pride have a brighter red tone to their eyes than the Pridelanders. Kiara's and Simba's orange-brown eyes are softer.
- The Lord of the Rings. The Nazgûl and the orcs (all very evil creatures) have glowing red dots for eyes.
- The PNK sorority girls in Monsters University. They're usually bubbly valley girl types, but when they get down to scaring, they hiss and their eyes glow red. Yikes.
- Monsters vs. Aliens:
- After being imprisoned by the military merely for being a 49-foot, 11-inch monster woman, Susan starts banging on the walls of her prison. The other monsters warn her not to do that, whereupon a huge door opens to reveal a dark interior with two glowing red eyes within... which merely turn out to be the lights on General Monger's Jet Pack.
- Played straight with the alien probe. When its eye turns red, there's little hope for you if you're in its way.
- In The Pagemaster Mr. Hyde has red eyes.
- My Little Pony: Equestria Girls – Rainbow Rocks: The Dazzlings get completely red eyes in their anthro-siren forms.
- In Pleasant Goat and Big Big Wolf - Mission Incredible: Adventures on the Dragon's Trail, when a certain character is about to snap the Dragon Den's key into pieces, his eyes turn red.
- Puss in Boots: The Last Wish features The Wolf with piercing red eyes. They stand out with his black sclera. Certain angles and lighting make them bigger and deeper. He is after all, Death.
- In Superman vs. the Elite once Superman decides to fake crossing the Moral Event Horizon, not only do his eyes glow red; the blood vessels in his left eye were damaged earlier in the fight, giving that eye a reddish tint, which only adds to how shit-scary he is at the time.
- In The Thief and the Cobbler, all of the One-Eyes (an evil race that plans to destroy an idyllic Golden Land) have a single, big red eye.
- Toy Story 2: Buzz Lightyear's archenemy, the evil Emperor Zurg, has glowing red eyes.
- Chef has red eyes, and is the villain of the first movie.
- Trolls World Tour has a downplayed case. Queen Barb has red irises, and anyone enslaved by her Mind-Control Music has their eyes turn completely red, but Barb herself is actually more of a Well-Intentioned Extremist, and the red color is rather used to represent the Rock Trolls.
- In Turning Red, whenever Mei is angry in panda mode, her eyes turn red. When not angry, her eyes are their usual brown.
- Lord Kuruku from Unico in the Island of Magic has red eyes.
- David Bowie's "Cat People (Putting Out Fire)", written for the 1982 film and re-recorded on Let's Dance, has a lovelorn man singing to an object of desire, warning her of the intensity of his need. The first verse establishes that his eyes are usually green, but they become red in the second verse:
"See these eyes so red
Red like jungle burning bright
Those who feel me near
Pull the blinds and change their minds."
- The Putin-P series features the Vocaloid Rin as its main character, whose eyes turn red when she reverts to Red Rin, a dangerous and Yandere part of her programming that's actually resultant of a virus inserted into her. Camui Gackpo, contrary to his official design, also sports these, and attempts to kill Rin in his introduction. Len remarks on it during their showdown.
- The Sweet's "Ballroom Blitz" mentions this about the man in the back. "As a matter of fact, his eyes are as red as the sun." He's responsible for it turning into the titular ballroom blitz.
- Gorillaz bassist and Magnificent Bastard Murdoc Niccals used to have one red eye and one black eye. The red eye appears to have turned black in recent pics, which may mean anything or nothing story-wise.
- In the animated video for Mystery Skulls' "Ghost", Mystery has red eyes. It simply appears to be because of his Color Motif being red at first, but later on he's heavily implied to be a Kitsune, and far more in the know than you'd expect. When this is revealed, his eyes glow red.
- The eyes of cemetery statue "Black Aggie" are said to glow bright red in the middle of the night, either blinding or killing anyone who looks into them (source).
- One Urban Legend/Creepypasta talks about a man who stays at a hotel but is told to stay away from a certain room. Out of curiosity, he peeps through a keyhole and sees an apparently normal room, with a woman sitting against a wall. When she moves, he backs away and returns to his room. Later, he tries looking in again, but he can only see something red through the keyhole. Not able to stand the questions any longer, he asks the hotel clerk what's wrong with the room. She tells him that, years ago, a couple died inside, and they tended not to mention it to avoid upsetting guests. She also mentions that the couple had unusually red eyes.
- The Urban Legends creature known as Mothman is said to have glowing red eyes.
- Most people associate red eyes with Demonic Possession and The Devil.
- Many Inuit legends feature the ijiraq, a shape-shifting creature that kidnaps children. No matter what shape an ijiraq shifts into, its eyes will always appear red.
- Avengers: Infinity Quest: Getting a tilt warning displays an image of Thanos with glowing red eyes, tying into his role as the game's Big Bad while also visually dissuading the player from playing rough with the machine.
- The antagonist in Centaur has small red eyes, as if his bestial face, inhuman form, and dominatrix-inspired design didn't raise enough warning flags.
- In Krull, The Beast's red glowing eyes can be seen o both the backglass and the lower-level playfield.
- Similarly, the monstrous Varkon has round red eyes, which combine with his small fangs and rounded, brutish face to complete his Monstrous Humanoid appearance.
- Charlie and the Chocolate Factory: In the 2017 Broadway retool, the squirrels' eyes glow yellow at first, but then glow red as they tear Veruca apart.
- The Haunted Mansion: In Phantom Manor (the Paris incarnation), the Phantom's eyes glow red at passing riders both times that you pass up close to him (after leaving the Bride's Boudoir, and when leaving Phantom Canyon).
- Zigzagged throughout BIONICLE, as the eye colors of the characters are all over the place, especially in the earlier years, though there are few straight/inverted cases:
- Naturally, the original Big Bad, Makuta Teridax, also had his trademark red eyes (which he liked to project into shadowy corners), (though in his original set form he had blue eyes with red sclerae),as did many of his brethren, as well as some other villains in the toyline (Krekka, Sidorak, Piraka, Keelerak spiders, etc.). Some, however, eventually substituted orange for red, when the eye colors became Colour-Coded for Your Convenience.
- In the movie Bionicle: Web of Shadows, Toa Vakama inverts this: he has red eyes until he goes over to The Dark Side, at which point, his eyes turn green. His toy, on the other hand, always had green eyes.
- The evil Roodaka from the same movie had blue eyes normally, but when she got really angry, they turned bright orange/red.
- When Teridax hijacks Mata Nui's body, his eyes go from yellow to red.
- LEGO Aquazone: The villainous Stingrays have red eyes, among other inhuman traits due to being mutants.
- In Code:Realize, glowing red eyes are a sign that the person in question is under the influence of Hidden Strength, a process which uses physical and emotional torture to unlock greatly enhanced physical abilities and leave them Brainwashed and Crazy.
- Danganronpa: Trigger Happy Havoc:
- Celestia Ludenberg fits this trope, since while they seem helpful and sweet in the beginning of the game, eventually she ends up responsible for two murders, and showed no mercy for it unlike the previous two murderers. Of course, even before that, she was pretty cutthroat and has always been a good liar.
- Kiyotaka Ishimaru technically fits - even though he never makes a Face–Heel Turn, his red eyes are a predicator for when he (possibly) absorbs Mondo's spirit and becomes the loud and aggressive Kiyondo Ishida — although even then it's a bit of a fake-out, as despite his more aggressive mode of speech he's just as harmless as Ishida as he was before. Unfortunately — and perhaps partially thanks to this trope — it's enough along with Celeste's manipulation to convince Hifumi that he needs to be put down for the good of the group.
- From Danganronpa 2: Goodbye Despair, Peko Pekoyama, the Ultimate Swordswoman has a very noticeable bright red color to her eyes. She's also something of a Perpetual Frowner and yes she is a dangerous individual, being a hitman for the Kuzuryu Clan of yakuza.
- In Danganronpa V3: Killing Harmony, Maki Harukawa is an uncooperative and brutally honest girl who's actually the Ultimate Assassin. Gonta Gokuhara, on the other hand, has red eyes and is a Gentle Giant (unless people insult bugs), but he ends up being manipulated into committing murder to Mercy Kill his classmates.
- Danganronpa: Trigger Happy Havoc:
- Wilhelm from Dies Irae is perhaps one of the most depraved villains in the story, and being an albino, he has bright red eyes. And the more and more he get's into a fight, the more his eyes start to glow and and take on Black Eyes of Crazy on top of it. This is especially noticeable when compared with the other albino of the cast, Claudia, who have golden eyes instead and is kindhearted to a fault.
- The dragonslayer's armor in Dra+Koi has glowing red eyes, suitable for its role as the sort-of antagonist.
- Solidly averted in Katawa Shoujo with Akira Satou, Lilly's easygoing Cool Big Sis. Well, there is the fact that she's quite happy to supply Hisao, Lilly and Hanako, who are minors, with alcohol.
- Nasuverse: A number of characters in the franchise have red eyes, and while it's rarely commented on in-story, a common thread is that all red eyed characters are supernaturally powerful in some manner. Characters like Gilgamesh or Cu Chulainn have divine blood, and their red eyes are an indicator of that. Vampires of all types have red eyes, and people turned into vampires will gain red eyes. Illya is a homunculus with tremendous magic power. In short, the red eyes do not indicate a character's morality, but anybody who does have red eyes is generally not someone you want to mess with.
- The vampires in Shall We Date?: Blood In Roses have this happen to them when they're about to drink a person's blood. If the vampire has made someone their belonging, their eyes will also turn red when they command the belonging to do something.
- The key art for Spirit Hunter: NG features the protagonist with a single, glowing red eye. This shows up once in the game; in the Bad End where he's been transformed into a bloodthirsty monster.
- Inverted in Suika. Shinigami have red eyes, but are exclusively the kindest and gentlest people who have died.
- Trapped with Jester: The only apparent orbs in Jester's eyes are red ones, which tend to show up with a sinister smile. When they appear, expect the screen to darken a bit. That is, unless he says you bore him, and he leaves you to die.
- In Umineko: When They Cry, the Stakes of Purgatory always wear these eyes. Considering that they are Beatrice's furniture, one can guess what happens when they're around...
- For a brief moment in fault milestone one, Rune has them as Ritona investigates the graveyard. While this was intended to make Rune appear more sinister than she actually was for that particular scene, it also foreshadowed the reveal that she was an automaton.
- AstroLOLogy: The usually nice Cancer will have her eyes go fully red whenever she gets angry at the other characters, though the other characters will have angry red eyes as well on occasion.
- This trope gets a Lampshade Hanging in DEATH BATTLE! when discussing the Robot Masters during the analysis section of Wily vs Eggman.
Boomstick: Metal Man was specifically made for killing things. You could tell, 'cause he's got evil red eyes.
- Dreamscape: Snowball, when in his adult bear form, gets red eyes.
- DSBT InsaniT:
- To show that ??? is evil, its the only thing that seperates him from Koden. Killdra even thinks he's just Koden high on drugs at first.
- The Darkness counterparts all have red eyes.
- The title character of Father Tucker had his eyes turn red whenever he got angry, which was usually when he threatened the children he molested into keeping quiet about his actions by claiming they'd go to Hell if they squealed on him.
- Glitchtale: After Asriel's SOUL is eaten by Kumu, Frisk is enraged to the point where their Level of Violence is immediately increased to 19, causing their eyes to open. Their eyes are glowing red as a result of their intense DETERMINATION.
- Lobo (Webseries):
- The titular character is a violent bounty hunter with red eyes and no pupils.
- The MBA are a race of ravenous alien zombies who have red eyes.
- Maxwell Edison, in an almost disturbingly well-done Flash video of The Beatles' "Maxwell's Silver Hammer", is depicted with red eyes.
- The Most Epic Story Ever Told in All of Human History: Ridiculously Epic, Epic Robot Guy, and Ridiculously Epic Fail all have red eyes and appear to be evil. Ridiculously Epic is outright confirmed to be evil when he destroys the moon and the sun at the end of the trailer.
- On the website Scratch, user Qem-95 does this on his "Thank you for 300 projects!" animation in order to make the screamer he pulls off on the viewer scarier.
- Yang typically has light purple eyes. However, should she get angry and start powering up her Semblance, her eyes turn red and flames burst forth from her golden hair. Characters in-universe learn to recognize very quickly what her eye colour change means and to either try to calm the situation down or go into battle mode themselves.
- The camera has a tendency to zoom in on Emerald's vivid red eyes whenever she's tapping into her mind control powers, which bodes ill for the target of her power. She can make a target perceive anything she wants, and all the senses are fooled, not just sight. Emerald's abilities are the main reason why Cinder is so successful in destroying Beacon Academy and becoming the next Fall Maiden. She enables Amber to be ambushed by making Amber think there's a crying child in need of help, and ensures Amber has troubling seeing exactly where Cinder, Mercury and herself are during their fight even when looking straight at them. She also fools Yang into seeing and hearing Mercury attack her from behind after their tournament ends, resulting in Yang appearing to the watching world as though she's attacked a badly injured and defeated Mercury for absolutely no reason. This disqualifies Team RWBY from the tournament.
- The Big Bad has eyes that are black pits with glowing red irises and elliptical pupils. They glow malevolently whenever they are feeling sadistic, asserting their dominance or revelling in the plans they have unfolding across the globe. Salem's eyes are similar to the glowing red eyes of the Grimm, and combines with her bone-white skin, red vein-like markings and black clothing to give her the appearance of a humanoid Grimm. Along with her ability to control the Grimm, this helps make it ambiguous as to whether she's human or something else until her backstory is revealed in Volume 6.
- Ceriazibus from the Sock Series has red eyes and is one of Sock's most dangerous monsters.
- In Daria Cohens The Vampair Series not only do the vampires have glowing red eyes but so does the evil magic cane.
- The superhero guide How to Hero lists red eyes as a surefire indicator that someone is an evil clone.
- Nobody Here: You can give red eyes to the creepy girl's face in "Present", if you so desire. More pressingly, she will always have glowing red eyes during the Jump Scare.
- SCP Foundation:
- SCP-1049 ("The Bonetaker Owl"). SCP-1049 is an owl that can suck a person's skeleton out of their body by biting them. It has red eyes.
- SCP-1111 ("The White Dog"). The title ghostly animal has red eyes that glow more brightly the closer it is to its point of origin. It savagely attacks all human beings that approach it.
- SCP-1461 ("House of the Worm"). In the accompanying story The Worm, exposure to the evil in the house changed some of the human workers into monsters with shining red eyes.
- SCP-1819 ("Darkness is Only Skin Deep"). The boogeyman that inflicts the dangerous SCP-1819 effect on children is described by the children as having a large "bright" or "burning" red eye.
- SCP-2901 ("Mothman"). SCP-2901's standard manifestation is a humanoid with dark-colored wings and large red eyes. They are known to attack human beings, especially when the humans flee them, and their touch causes the victim's skin to be ripped off. They also appear near the sites of disasters and eat the bodies of the victims.
- 7-Second Riddles: A monster under a kid's bed is shown with bright red eyes, while holding a knife, and smiling evilly.
- Oswald Sherzikien's eyes turn red when he becomes a gigantic cartoon monster near the end of Journey of the Cartoon Man
- Zigzagged in Critical Role. Mollymauk's eyes are entirely red, lacking both a pupil and an iris. This in itself doesn't actually mean much; Molly's red eyes are due to his tiefling heritage, and while he can be abrasive, he is a genuinely nice person. What is strange are the nine red eye tattoos placed randomly across his body, especially since Molly himself woke up with complete amnesia about two years prior to the start of the story and has no idea where they came from. It's not until the final arc of the story, months after Mollymauk's death, that the Mighty Nein encounter Lucien, the person Molly was before losing his memory. Unlike Molly, Lucien knows that the red eye tattoos are gifts of the Somnovem, and can use them to devastating effect; summoning fireballs, creating an anti-magic field, and unleashing a psychic assault that nearly One Hit Kills Beau and Caduceus.
- Dad: In "Dad Loves Mom", it's mentioned that when Mom is upset, "her eyes glow red"; with the implication that the family aren't even human, it's likely this isn't just figurative.
- In Heat vs Repulsion video, when heat was pissed off. Cue epic music. Watch it here
- Logan's Tale: Raiders in the Capital Wasteland often have red eyes. Logan speculates that it's an effect of the chems they take.
- In Microsoft Sam Reads Funny Windows Errors, when ever Sam is seen with red eyes, it's not a good sign.
- In Minecraft Diaries, Shadow Knights possess these in only their Shadow Knight forms if they have yet to gain their immortality, and all the time if they have done so. (At least, in most cases).
- Played for Laughs when The Nostalgia Chick reviewed My Little Pony: The Movie (1986): a certain pony had red eyes for no apparent reason. Every time she came on screen ominous music would start playing and the Chick would freak out.
"And what's with your demon eyes?!"
- The Weather: At the end of The Wizard of Oz segment, Alan, revealed to be a murderer and manipulator, talks to Toto — who is the only caller with red eyes rather than white, along with a deep voice. They've apparently been the one to convince Alan that everyone else is crazy, and it's implied that this is more-or-less a crazy Alan thinking he's talking to a demon dog.