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Nyaruko
Voiced by: Kana Asumi (Japanese), Valca Ponzanelli (Latin American Spanish)
An energetic silver-haired girl who happens to be an anthropomorphized form of the Crawling Chaos, Nyarlathotep.
- The Ace: She is beautiful, athletic, intelligent, makes friends easily, is a good cook, her family's golden child, and a famous and respected space cop. If not for her flaws (namely her clinginess, playful fibbing and inability to operate at a level below "Overdrive") being so blatant, she would easily fall into Mary You-Know-Who territory.
- Adaptational Heroism: Nyarko may be a bitch, but compared to the Cthulhu Mythos' Nyarlathotep she is a saint. While the original Nyarlathotep was a malicious Troll, she is more like a Manic Pixie Dream Girl with Troll tendencies toned down: she drives Mahiro up the wall by being so goofy and telling Blatant Lies (like claiming he got her pregnant), but rather than malice she does it because she has a hard time expressing her feelings for him any other way.
- Anguished Declaration of Love: Declares her love for him while crying her heart out after seeing him and Cuuko being too close to each other, which causes her insecurities about his true feelings for her.
- Badass Adorable: Look at that shining smile and those huge emerald eyes. Look at her cutting a nightgaunt in half with a crowbar.
- BFS: In the last episode of the TV series, she turns her crowbar into one using The Power of Love (which Mahiro immediately denies).
- Bodyguard Crush: Literally begged her superiors for the mission to protect Mahiro after seeing his picture.
- Bully Hunter: In Nyaruani, when asked as to why she is in love with Nyarko, Cuuko claims the latter once beat up her bullies from way back in space kindergarten. Subverted later when Nyarko admits that she beat up anyone she found playing make-believe, even Cuuko.
- Played more literally later in the novels, where we learn that she and Cuuko would beat up their space elementary school classmate Nyogta for his bullying Hasta. Which causes a grown-up and bitter Nyogta to erase the girls from existence.
- Casual Kink: Very open about her perversion, which turns Mahiro off.
- Catchphrase: "I'm the Crawling Chaos who's always creeping up on you/Mahiro-san with a smile!"
- Chainsaw Good: Yes, even a chainsaw is considered Space CQC.
- Chaos Is Evil: Played with. Like her namesake, Nyarko refers to herself as "The Crawling Chaos", but she isn't outright evil. However, she does annoy Mahiro, shows no mercy to her enemies, and has no qualms bending the rules to suit her needs.
- Chekhov's Skill: The "battle" with Agent Smith turns the "Cyclone!" JOKER!!" Overly Long Gag into one of these, as Nyarko's ability to create Joker cards lets her easily beat Smith. Eternal trump card indeed...
- Cleavage Window: Her Planetary Defense Organization uniform (seen in Nyar-O's flashback in episode 3) sports one.
- Clingy Jealous Girl: She will never let anyone take Mahiro away from her.
- Color Failure: Only second to Mahiro in frequency.
- Combat Pragmatist: In every possible way. In the first episode she knees a Nightgaunt between the legs and then proceeded to bash the thing's head in with a rock.
- Cool Sword: Her official list of powers include "a mechanical sword capable of cleaving dimensions"...better known as Kamen Rider OOO's Medajalibur. In the anime she only uses it in Nyarko-San W episode 9, as part of a mass of references to OOO.
- Crazy in the Head, Crazy in the Bed: She is a Cute But Psycho Lovecraftian horror in form of a girl that has a Mad Love obsession with Mahiro. When she does finally manage to sleep with him, the experience lasted hours and Mahiro passed out from screaming so much.
- The Cuckoolander Was Right: Happens pretty often, much to Mahiro's annoyance. A specific example is her suggesting that Mahiro is descended from a famous deity hunter based off of his Tsundere attitude and skill with forks; Mahiro dismisses it as nonsense, but then his mother comes home and we learn that Nyarko was spot-on.
- Also happens with her attempts to pick out the Chekhov's Gun that will be critical to the current case; again, Mahiro will dismiss her suggestions because they would lead to a stupid resolution, but her guesses have been right more often than his thus far.
- During the "Freaky Friday" Flip plot, Nyarko even laughed with Mahiro at her own suggestion that the time-travelling rebel had stolen Yoichi's body, saying it would be way too convenient. So of course, it turns out she was right.
- Cute and Psycho: She's cute and bubbly and downright vicious in combat. She's even worse when she becomes a Magical Girl, where she sets Nightgaunts on fire and makes them puke blood while going on about "purifying naughty childrens' souls".
- Cute Bruiser: Her fighting style isn't exactly sophisticated, utilizing fists, kicks or some blunt instrument.
- Cute Little Fangs: She has feline fangs to match her energetic and mischievous personality.
- Disney Death: In Episode 10. She's actually fine — the black crystal she gave to Mahiro back in Episode 2 saw to that.
- Even the Girls Want Her: Just ask Cuuko.
- Everyone Has Standards: She may be a Lovable Sex Maniac, but even Ato-ko creeps her out.Mahiro: Nyarko, can I punch her?
Nyarko: Please do. - Expressive Hair: Nyarko's cowlick can even form letters.
- Genki Girl: And probably the most energetic Nyarlathotep ever.
- Gone Horribly Wrong: Mahiro has her become a Magical Girl in the hopes that it'll mellow her out; it seems to work for approximately ten seconds, then she runs off to fight some Nightgaunts and acts outright Axe-Crazy, as opposed to her usual Cute and Psycho merciless fighting style.
- Gratuitous Foreign Language: Primarily English. Also, Italian.
- Henshin Hero: With blatant nods to Kamen Rider, the Trope Namer franchise.
- Heroic BSoD: Has a brief one when Mahiro and Cuuko have to pretend to be lovers, and he tells her to go home if she doesn't want to see them like that.
- And again in the last episode of Nyarko-san W when ordered to leave Earth, but it really kicks off after Mahiro sadly says "I can't do anything to stop it". She spends the next half of the episode with Hidden Eyes and utterly silent, literally having to be dragged along by the hand by Mahiro.
- Heroic Comedic Sociopath: Mahiro's reaction to most of her methods is to wonder if she is the same as her enemies, and she's prone to lots of Nominal Hero moments.
- Holy Hand Grenade: Nyarko uses blasphemous hand grenades. Yes, actual hand grenades (with little pink ribbons around them).
- Hypocritical Humor: Cuuko is a clingy unwanted love interest to Nyarko...just like Nyarko is a clingy, unwanted love interest to Mahiro. Often Nyarko will even direct insults against Cuuko that she heard from Mahiro not minutes earlier.
- Idiot Hair: She has a very long hair sticking out from the top of her head. It suits her silly character.
- I Have Many Names: A search for her name in a library database brings up so many alternate names the system crashes.
- Incoming Ham: Whether it's imitating another Large Ham ("Watashi, SANJOU!") or introducing herself with the Opening Narration from Galaxy Cyclone Braiger, you know exactly what to expect when Nyarlathotep walks into the room.
- In-Series Nickname: A double example, with "Nyarko" being short for "Nyarlathotep", and that name being what people call her because her real name is The Unpronouncable.
- Involuntary Shapeshifting: The light novels explicitly state that she has the power to transform others into weapons or vehicles, a Shout-Out to Kamen Rider Decade's Final Form Ride; she uses this in the anime to turn Shantak-kun into a Cool Bike, and Hasta into his Super Mode.
- Large Ham: She's basically the personification of hamminess.
- Let's Get Dangerous!: While she acts like a buffoon most of the time, when things get serious, she can really kick some ass.
- Lovable Sex Maniac: Much to Mahiro's chagrin, Once an Episode she's either trying to bed him or at least talking about it very loudly.
- Love Before First Sight: She was smitten with Mahiro with just looking at his photo.
- Lust Object:
- She wants to be this for Mahiro, but her sexual advances only turn him off.
- Cuuko wants to get banged by Nyaruko badly. Cuuko doesn't even care if there's another person inside Nyaruko's body, she only wants to get her hands on it.
- Mad Love: Her very clingy and stalker-y tendencies as well as her very forceful advances make her a nuisance to Mahiro more than anything and he keeps telling her to just leave him alone. He does like her deep down, but still finds her way too annoying for his tastes.
- Magical Girl: Becomes one in "How to Defeat a Kind Enemy" at Mahiro's insistence in the hopes that it'll make her less hyper and violent. It completely backfires.
- Even as a Magical Girl, she references Kamen Rider Kuuga and Dancougar; you can take the tiger out of the jungle, but you cannot take the jungle out of the tiger.
- Magical Girlfriend: She's the alien anthropomorphized form of Nyarlathotep the Crawling Chaos who is sent to Earth to protect Mahiro and falls completely in love with him. Her arrival is just the beginning of the new craziness in Mahiro's life.
- Malaproper: Happens as a result of her use of Gratuitous English; the most famous example is confusing "hate" and "(land)mine", because they're homophones in Japanese (kirai).
- Manic Pixie Dream Girl: As noted elsewhere, this actually works to her disadvantage, since she's a bit too manic and clingy for Mahiro's tastes.
- Man, I Feel Like a Woman: Obviously her first order of the day after being stuck in Mahiro's body.
- Master of the Mixed Message: Nyarko will gladly, eagerly, tell Mahiro that she loves him. However, in episode 7 of the second TV series, he complains that her wacky, playful nature and near-constant lying makes it so that he isn't sure she even really means it. Nyarko calmly responds that she has trouble saying it unless she's acting silly, but assures him she's completely honest. She then turns, smiles, and simply says "Mahiro, I love you."
- Meido: Her "default" outfit
is actually a maid outfit; it's just less obvious because of the black apron and checkerboard-patterned bow and skirt. - Moe Anthropomorphism: She's part of an alien race based on Nyarlathotep, the Crawling Chaos. She shows herself as a cute teenage girl and claims that this is her true form, but might have just been screwing with Mahiro's head. We have seen her brother take on an Eldritch form, though, so it stands to reason she can do much the same.
- Moment Killer: To her own romantic moments with Mahiro — just when he is ready to finally admit he loves Nyarko, she ends up unwittingly driving him off again by topping her previous horny behavior.
- Motor Mouth: Nyarko will talk non-stop. About anything you haven't asked her about, of course.
- Mystical White Hair: She's a Human Alien with long silver hair.
- No Sense of Personal Space: In addition to constantly clinging to Mahiro like a barnacle, she repeatedly tries to jump him in the bathtub or the bedroom and "play Adam and Eve".
- Not Cheating Unless You Get Caught: When asked by Mahiro about whether she can bring home all the manga, anime and games she bought at Akihabara, and whether this makes her the same as the smugglers she's supposed to apprehend, her reply is...Nyarko: "It's not a crime if no one finds out."(Cue Mahiro showing her a video saying that exact line on his camera)
- Oblivious to Her Own Description: When the Banshin starts obsessing over Mahiro and doing Henshin Hero poses, Nyarko thinks it's short-circuiting. She doesn't realize that it's acting exactly like her until Mahiro outright tells her as much...at which point she thinks it's awesome.
- Only Known by Their Nickname: When she introduces herself to Mahiro, she says "They call me Nyarlathotep, but I actually have a real name"; later novels reveal that her name is unpronouncable by human tongues, and just being able to comprehend it is a feat in and of itself, one that apparently helps you understand her better and makes you emotionally closer to her.
- Opposites Attract: She's an alien who pretty much embodies nonsense and is crazy about Mahiro, a no-nonsense everyman.
- Pop-Cultured Badass: Nyarko will beat the snot out of you while doing Kamen Rider poses, quoting Jotaro Kujo, using Ranma Saotome's tactics, and much, MUCH more.
- Red and Black and Evil All Over: The color scheme of her Full Force Armor, though she's not really evil... just violent and perverted.
- Ret-Gone: She and Cuuko get written out of existence by their old classmate Nyogta, but get restored by Mahiro and Yithka.
- Rocket Punch: In episode 11 of Nyarko-San W, she executes Kamen Rider Fourze's Rider Rocket Punch on Cuuko; the light novels outright state that she has the power to manifest "an orange rocket-like propulsion unit" on her right arm.
- Rule of Cool: The light novels demonstrate that she can change into her Full Force Form with nothing but a thought; she just chooses to do Kamen Rider poses and say "Henshin!" because she's a fangirl and thinks it's awesome.
- Savvy Guy, Energetic Girl: She's the hyperactive Energetic Girl to Mahiro's down-to-earth Savvy Guy.
- Say My Name: "Maaahiro-san~!" So much that it's practically a Catchphrase in and of itself.
- Self-Proclaimed Love Interest: She claims to be Mahiro's wife, to his chagrin.
- Shameless Fanservice Girl: She tries to show off her naked body to Mahiro more than once, only for him to tell her to put her clothes on.
- Single-Target Sexuality: Has made it very clear that she considers Mahiro Yasaka her ultimate, eternal, one-and-only love and that nobody else in the universe could ever hold a candle to him.
- Smitten Teenage Girl: Her infatuation with Mahiro lacks any logic or restraint.
- Space "X": She refers to her fighting style as Space CQC.
- Speaks Fluent Animal: She can understand what Shantak-kun is saying without the need for a translator like Kuuko.
- Spell My Name With An S: Her name is obviously supposed to be Nyarlathotep plus the Japanese suffix -ko, which is used to "feminize" a name (such as Kyo -> Kyoko). This means that Nyarko, Nyaruko, and Nyarlko are all perfectly valid spellings.
- Stalker with a Crush: She has an obsessive crush on Mahiro and chases after him every day.
- Super Mode: Her "Full Force Form", which she first used to beat Cuuko after losing to her initially due to the latter's power boost in her own pocket dimension.
- Super-Speed: The light novels list Clock Up as one of her special powers; so far it's only been referenced for the sake of a gag.
- Teen Genius: Goes back since childhood, much to her older brother Nyar-o's ire.
- That Liar Lies: No, she does not carry Mahiro's child. Doesn't stop the rest of the cast from believing her, though.
- Trouser Space: Nyarko keeps a chainsaw in her skirt. You read right. Her magical girl form keeps her trademark crowbar there.
- The Unpronounceable: Nyarko's real name is apparently extremely difficult for humans to pronounce; just comprehending it is said to strengthen the relationship between a man and a woman.
- Victoria's Secret Compartment: She keeps a full-size Pokeb-I mean, Monster Capsule inside her blouse, as well as her candid pictures of Mahiro.
- Violently Protective Girlfriend: Picking a fight with her is never a good idea; hurting Mahiro, however, invites a far worse response from her. Cuuko found out the hard way when she stated that she was going to toast Mahiro.
- Voluntary Shape Shifter: According to the Light Novel, all Nyarlathotepians can shift their facial features at will; Nyarko uses this to prove she's an alien by making herself look like an expy of Nanoha. Additionally, she can change into her Full Force Form with just a thought.
- White Hair, Black Heart: Less evil, more "perverted".
- Wingding Eyes: Gets visible stars in her eyes when visiting Akihabara.
Mahiro Yasaka
Voiced by: Eri Kitamura (Japanese), Ivan Garcia (Latin American Spanish)
A 17-year-old high school boy with a fascination for the Cthulhu Mythos.
- Action Survivor: He's been in close contact with the denizens of the Cthulhu Mythos... and he's still not insane.
- Adaptation Dye-Job: Has black hair in the light novels, which gained a dark brown tint in the anime. On a similar note, his eyes went from brown in the novels to grey in the anime.
- Ascended Fanboy: Though in this case it's an extremely mixed blessing.
- Aw, Look! They Really Do Love Each Other:
- When Ato-ko shows up in the novels, she puts Mahiro in a fantasy sequence to determine who he really loves — and we get an Imagine Spot of him and Nyarko getting married.
- Likewise, when Nyarko confesses her feelings in front of her parents, Mahiro simply turns bright red instead of getting freaked out like usual.
- Badass Normal: On the rare occasion that he gets to fight, he holds his own among cosmic horrors with nothing but a fork.
- Beware the Nice Ones: He may seem to be a hapless boy, but push him too far — especially make fun of the Cthulhu Mythos — and he will stab you with a fork... whether you're human, animal or Lovecraftian.
- Berserk Button: Never ever malign the Cthulhu Mythos.
- Brutal Honesty: Tends to be very direct with his thoughts about all the Lovecraftian insanity around him. In one case, he even made Nyarko lose almost all her SAN Points by directly telling her that he doesn't like her.
- Cannot Spit It Out: In episode 5 of Nyarko-san W, he mutters to himself that he would probably be more interested in Nyarko if she was not so manic; he actually says this in Nyarko's presence, but refuses to repeat himself when she says "What did you say?".
- Can't Act Perverted Toward a Love Interest: In the wake of his body-swap with Nyarko he cannot even find the courage to look at the latter's naked body while taking a bath.
- Can't Stand Them, Can't Live Without Them: Mahiro constantly says how annoying his alien housemates are and stabs them with forks when they take their antics too far. When he's left completely alone in an alternate dimension, he starts missing them and realizes he does think it's fun to have them around.
- Catchphrase: He has a couple: "Wait, that makes no sense"note , "That was another stupid ending" and "Keep it to three lines"note
- Color Failure: The poor boy is prone to this, be it for failed SAN Meter checks or having his mom returning without warning.
- Crazy-Prepared: Be it forks to fend Nyarko off or a cellphone with camera with which he can blackmail her into doing her job properly. He takes this to another level in Episode 7 of Season 1, where he's got enough forks to pin Nyarko to a table for the whole night after she tried to make their "love take form".
- Crossdressing Voices: Eri Kitamura is more used to younger girls and kids, not a boy in his mid-teens like him.
- Averted (kind of) during Mahiro and Nyarko's "Freaky Friday" Flip and Kitamura gets to "play" Nyarko.
- Did You Just Punch Out Cthulhu?: He subdues Nyarlathotep with forks roughly Once an Episode.
- Did You Just Romance Cthulhu?: He got Nyarlathotep to fall for him; he might consider it unfortunate (for now), but some fans tend to think he's an idiot for being less-than-receptive to the hot silver-haired geek girl who totally wants to play Adam and Eve.
- Disappeared Dad: His father's alive and well, but he has yet to appear in either the novels or the anime. It's implied that he's stuck at work almost constantly to make up for all the honeymoons he goes on with Yoriko.
- Domestic Abuse: His physical violence on Nyarko and Cuuko are treated as comedy.
- Empowered Badass Normal: The novels later reveal an ability to perceive fluctuations in spacetime and a much higher than normal resistance to You Cannot Grasp the True Form. Together with the curious appeal he has to the series various aliens that first kicked off the series, it hints he might not be entirely normal after all, especially given his parent's established connections to the eldritch world...
- Fork Fencing: Uses forks as weapons, claiming they are the most powerful weapons in the universe.
- Friend to All Children: His interactions with Guthatan, Hasta, and the human-ized Shanta-kun show that he's quite fond of kids. He's even admitted to viewing Hasta as the little brother he never had.
- Gratuitous English: Courtesy of episode nine's introduction. CLOSE. YOUR. EYES.
- Improbable Aiming Skills: In episode 9 of Nyarko-San W, he hits a triple 300 on a dartboard...again, with forks.
- Improbable Weapon User: When he has to, he fights with his trusty... fork.
- Informed Attractiveness: He looks like an ordinary Japanese teenager in terms of design, but he's still considered handsome enough to have smitten Nyarko just with his photo, get "scouted" for a role in an alien boys' love show (he was not pleased with this), and get confessed to by Hasta. At one point the girls tell him that he's strangely attractive to aliens.
- Kid with the Leash: He does his best to keep Nyarko's, Cuuko's, and, sometimes, Hasta's antics under control.
- Luminescent Blush:
- Mahiro gets one after seeing Nyarko's panties, and also when he takes one of her advances seriously — sometimes Played for Laughs.
- At the very start of the story, he gets one at the idea of having a pretty girl like Nyarko being around him day and night; when she notices and calls him cute, out comes the fork.
- In the novels, he gets one during his first meeting with Nyarko's parents when she she tells them that she's in love with him.
- Lust Object: When Nyaruko isn't trying to get in bed with Mahiro, she's imagining it or talking about it. This is why Mahiro doubts whether she sincerely loves him or is only trying to toy with him.
- Megaton Punch: He punched Nyarko so hard that she was sent flying high in the sky, in episode 5 of season one.
- Mr. Fanservice: In-Universe, he's a sexual god as far as the Lovecraftian deities are concerned.
- Nice Guy: He is legitimately a good, caring persion; he just has a short temper when it comes to Nyarko and co.'s madcap antics.
- No Guy Wants to Be Chased: He finds Nyarko way too clingy for his taste and her Lovable Sex Maniac antics put him off even more. He feels the most attracted to her when she calms down and isn't trying to force her way into bed with him. Too bad Nyarko doesn't get this and her friend Tamao just encourages her to be more aggressive whenever she wonders if she's pursuing Mahiro the right way.
- Non-Action Guy: Not that he cannot hold himself in a fight, but when he has Eldritch Abominations chasing after him, he would be powerless without Nyarko, Cuuko and Hasta rushing into his defense.
- Not So Above It All: In episode 3 of Nyarko-San W, it turns out that he was the one carrying the mystical book that the villains wanted; he has a Big "NO!" and Nyarko complains about how mean and hypocritical it was for him to try and pin this one on her. He defends himself by saying that that's usually how it works, only for Cuuko to call him out for making excuses.
- Only Sane Man: The only normal, reasonable person in a show full of weird and perverted aliens.
- Opposites Attract: With Nyarko. He's a no-nonsense everyman and she's an alien who pretty much embodies nonsense. Although he's annoyed by her antics, Mahiro does like Nyarko back.
- Ordinary High-School Student: He's a normal high school boy whose ordinary life turns into absurdity because of the arrival of the alien girl who is madly in love with him.
- Ripple-Effect-Proof Memory: He has the extremely rare ability to perceive and resist shifts in the space-time continuum; this gets brought up in the first novel when dealing with Nodens and Cuuko, but becomes a Chekhov's Skill later when Nyarko and Cuuko get written out of existence and Mahiro is the only one who can save them. Considering the series' love of Kamen Rider, this may well be a Shout-Out to the concept of Singularity Points from Den-O.
- Savvy Guy, Energetic Girl: He's the down-to-earth Savvy Guy to the hyperactive Nyarko's Energetic Girl.
- Shared Family Quirks: He inherited his fork-wielding skills from his mother Yoriko.
- So Beautiful, It's a Curse: To the viewers, he looks like an ordinary but still cute anime boy; to the aliens of the Cthulhu Mythos, he's apparently sex on legs, which means he's been scouted for a Boys' Love TV show, had a Yaoi Doujin written about him, and keeps having aliens fall in love with him.
- Straight Man: His main role in the show's comedy is to react to the absurdity going on and put up with his housemates' crazy antics.
- Tsundere: A male Sweet Type — he's a genuinely nice and friendly guy by default, but has little to no patience with Nyarko and co.'s madcap antics. These tendencies are more prominent with Nyarko; he claims to hate Nyarko's open affection, but no matter how often he brings out the fork, he obviously finds her cute.
- Unfazed Everyman: After a while, even Nyarue's true form doesn't really trouble him. In episode 2 of the second series, Nyarko even remarks that his tolerance for this sort of thing is pretty impressive.
- Unwanted Harem: Nyaruko is crazy for him, Cuuko eventually wants to have him and Nyaruko, Hasta wants to have his baby and Tamao has a little crush on him. Even Nyaruko's pet Shantak-kun loves him!
- Weirdness Magnet: Nyarlathotep the Crawling Chaos appearing in his life and declaring her undying love for him is just the start of his troubles, which includes dealings with time-traveling Moral Guardians, alien Animal Wrongs Groups, and being kidnapped so he can be auctioned off as the star of a Boys' Love TV show. Lampshaded in one episode where Nyarko remarks that something about Mahiro makes him "strangely attractive" to aliens.
- We Want Our Jerk Back!: In "How to Defeat a Kind Enemy", he makes Nyarko become a Magical Girl because he hopes it'll mellow her out; when this turns her outright Axe-Crazy, he admits that she was better the way she was.
- Would Hit a Girl: With Nyarko around, it's either hit or get hit on. He usually chooses the former. He has also hit Cuuko as well, although not nearly as much as Nyarko.
- Wrong Genre Savvy:
- Mahiro has claimed to be Player Character in Call of Cthulhu, which makes him afraid Nyarko will turn out to be just like the Lovecraftian Nyarlathotep. If he realized he was in a Lovecraft Lite Rom Com and that Nyarko actually is in love with him, he would probably be a lot happier. She is driving him insane, just not in the way he's thinking.
- Mahiro has also attempted to spot the Foreshadowing in advance, mostly by asking "What would make for the dumbest resolution?" So far he's only been right once (in episode 9 if Nyarko-San W); the rest of the time he's wrong because something comes out of nowhere and results in an ending even dumber than he anticipated.
Cuuko
Voiced by: Miyu Matsuki (Japanese), Marysol Lobo (Latin American Spanish)
Nyarko's old friend/enemy/stalker who also comes down to Earth and the humanized version of Cthugha, the Burning One.
- Abhorrent Admirer: She relentlessly chases after Nyarko who tries to get away from her all the time.
- Attack Drones: She controls drones that fire lasers. She refers to them as space CQC - Cthugha version and they look like a fusion of the Elmeth and Sazabi's respective attack drones.
- Badass Adorable: Watch her resort to adorably crazy ways to win Nyarko's heart one minute, then watch her incinerate nightgaunts, ghouls and Deep Ones the next.
- Bully Hunter: Back in space elementary school, she and Nyarko would rough up their classmate Nyogta for bullying Hasta; years later, he tries to get revenge by rewriting them out of history.
- Childhood Friend Romance: She has known Nyarko since space elementary school and isn't shy to express her wish to marry her.
- Childhood Friends: She was classmates with Nyarko and Hasta at space elementary school.
- Childhood Marriage Promise: Her cousin Cuune claims one...except that it consists entirely of a tape recording of a young Cuune coaching an even younger Cuuko to say things like "I want to marry cousin Cuune when I grow up". Nobody questions how this is a valid marriage contract.
- Clingy Jealous Girl: She will never let Mahiro have Nyarko all to himself. Luckily for her, Mahiro is more than happy to cooperate with her to get Nyarko off him. She still burns with anger whenever she thinks he made a pass at Nyaruko (although it's always Nyarko at fault). Later on, she wants to have both Nyarko and Mahiro, but doesn't like to see them close to each other without her permission.
- Creepy Monotone: Talks in a low, slow monotone, except when she talks to or about Nyarko.
- Curtains Match the Window: Sports red hair and matching eyes.
- Deadpan Snarker: She's a sarcastic with a dry sense of humor. Except where Nyarko is concerned, at which time she enters fangirl mode.
- Defrosting Ice Queen: She's initially cold and indifferent to anyone other than Nyarko, but becomes way friendlier to Mahiro as the series goes on. This culminates in Cuuko deciding she's fine to have both Nyarko and Mahiro.
- Dude, She's Like in a Coma: Technically only a rejection-induced shock, but she still has no qualms whatsoever about undressing Nyarko.
- Elemental Hair Colors: She has Playing with Fire powers and red hair to match her element. Also counts for Elemental Eye Colors because of her red eyes.
- Full-Frontal Assault: Her Cross Fire Sequence form can be seen as a Barbie Doll Anatomy version of this trope, as her "clothing" during it is either really good body paint or markings on her body.
- Gamer Chick: One reason she quickly became friends with Yoriko.
- Girlish Pigtails: Her hairstyle consists of two long twin-tails. She isn't exactly childish, but she's obsessive and immature.
- Guilty Pleasure: Toku, apparently; in "How to Defeat a Kind Enemy", she's watching Iron Striver as intently as Nyarko and refers to it as "predictable yet enthralling".
- Harem Seeker: After warming (pun not intended) to Mahiro, her plan changes from "marry Nyarko" to "I bear Nyarko's child, the boy bears mine". When he questions it, she responds by saying "My party system supports up to four characters."
- Hey, You!: Tends to call Mahiro "Boy".
- Hopeless Suitor: She's obsessed with Nyarko, but Nyarko doesn't have the slightest interest in anyone who isn't Mahiro.
- I Am Not Left-Handed: In her first fight against Nyarko, she reveals that she's able to use more Attack Drones than when last they met.
- If It's You, It's Okay: She is madly in love with Nyarko, but she also develops some feelings for Mahiro.
- The Immodest Orgasm: Miyu Matsuki does an exceptionally loud, erotic cry in Episode 5 of W when Cuuko is being felt up by Cuune.
- Incompatible Orientation: To Cuuko's bad luck, Nyarko would never feel attracted to another woman unless that woman is a Gender Bender Mahiro.
- Insane Troll Logic: The girl just runs on this.
- Irony: She's living fire, and yet is a nekojita (literally "cat's tongue") — someone who cannot handle hot or spicy foods.
- It Meant Something to Me: In order to discourage Cuune, she has Mahiro fake a relationship with her, but falls for him for real.
- I Want My Beloved to Be Happy: A small version occurs in episode 12 of Nyarko-san W. Cuuko, seeing how broken up Nyarko is after they're ordered to leave Earth, encourages Mahiro to be near Nyarko in the hopes of cheering her up (though Cuuko insists it's just a temporary "loan").
- Laser-Guided Karma: Volume 6 of the light novels introduces her cousin, Cuune. She acts the exact same way Cuuko does towards Nyarko, except she's horny for Cuuko.
- Lovable Sex Maniac: Just as much as Nyaruko, even though the latter won't admit that. Cuuko is very vocal about wanting to get into Nyaruko's pants and is trying to get her hands on her whenever she can.
- Lust Object: To her cousin Cuune. The first thing Cuune does when she sees Cuuko again is to jump at her, grope her all over and finger her.
- Mad Love: To Nyarko, she's nothing but her annoying, psychotic Stalker with a Crush, yet Cuuko won't get off her back no matter what she does to keep her away from her and Cuuko is ready to kill anyone who gets Nyarko's attention.
- Matchmaker Crush: Wholeheartedly ships Mahiro/Hasta at first, because it means that she can have Nyarko for herself. Hasta runs with it, to both Mahiro and Nyarko's annoyance. This changes once Cuuko falls for Mahiro herself and changes her plan to marry both Nyarko and Mahiro.
- Moe Anthropomorphism: She's a living fireball in the form of a cute red-haired girl.
- Murder the Hypotenuse: Briefly attempted this in her first appearance when she got annoyed with Nyarko's attachment to Mahiro, which prompted Nyarko to pummel her. Nyarko never brings up to Mahiro that Cuuko tried to murder him.
- NEET: She refers to her time as a "home security guard", a Japanese slang for this trope. Nyarko outright calls her a NEET a few times, as well as a Hikkikomori.
- New Job Episode: Has one in "Remember my Love(craft-sensei)", which she tries out various Earth jobs. None of these last due of her fire powers, was it "overcooking" steak (convenience store cashier) or her temper getting the best of her (fast food restaurant cashier).
- Or in the case of the last one (gas station attendant), Mahiro outright says "You shouldn't be working here."
- Nosebleed: In "How to Defeat a Kind Enemy", when Crawling Nyarko pulls her crowbar out from her skirt.
- The Not-Love Interest: Throughout the first season, Cuuko moves into Mahiro's house and joins Nyaruko's and Hasta's antics like she was another member of his harem. The thing is that Cuuko is after Nyaruko, not Mahiro. It gets subverted in the second season where Cuuko does develop some feelings for Mahiro. Her main target of affection is still Nyaruko, though.
- Otaku Surrogate: Of the general variety. During her first appearance she references Mobile Suit Gundam and The Big O, but this soon expands to video games and anime series, classic and contemporary alike.
- Playing with Fire: As a Cthugaian, she's able to control fireballs and heat.
- Plucky Girl: Willing to go to some crazy lengths to get into Nyarko's skirt.
- Psycho Lesbian: Subverted. Cuuko claimed she was going to kill Mahiro for being Nyarko's love. She changes her mind after Mahiro makes clear he would like Nyaruko to leave him alone too. From then on, Cuuko's attempts to sabotage his relationship with Nyaruko are limited to attempting to pair him off with someone else.
- Punny Name: Her name sounds like Kuudere, and she's a pretty classic type 3. She's also undeniably cuckoo.
- Ret-Gone: She and Nyarko get written out of existence by their old classmate Nyogta, but get restored by Mahiro and Yithka.
- Screw the Rules, I Have Connections!: Gets an easy pass into the Planetary Defense Force because her uncle happens to be in PR. Nyarko is incensed, since she had to pass an examination to even make it (as well as a few other reasons).
- Self-Proclaimed Love Interest:
- She calls herself Nyarko's wife even though the latter can't stand her.
- Later on, she calls herself Mahiro's fiancée even though they don't have to keep up the charade without her cousin around.
- Shipper with an Agenda: She ships Mahiro with Hasta so she can have Nyarko to herself, although she later changes her plans about Mahiro.
- Signature Headgear: She ties up her twintails with black ribbons shaped like flames.
- Single Woman Seeks Good Man: It's Mahiro's kind and helpful personality which makes Cuuko develop feelings for him.
- Stalker Shrine: Her room is full of pictures and figures of Nyarko and a body pillow.
- Stalker with a Crush: Her crush on Nyarko is as obsessive as Nyarko's crush on Mahiro.
- Sugar-and-Ice Personality: Icy, unemotional and monotone at first glance, but maniacally affectionate towards those she becomes obsessed with. At first Mahiro gets the coldest ice, only Nyarko gets the sugar. The former doesn't mind, so long as they remain on cordial terms. The latter would rather get away from her. Eventually Mahiro also gets the sugar, depending on the moment he can find it annoying or cute.
- Super Mode: Her Cross Fire Sequence, AKA "the battle mode where it looks like she's just wearing body paint".
- Trouser Space: She keeps her funnels in her skirt when in her school uniform. Later on it is revealed that she keeps a two-handed sword, of all things, down there as well.
- Vapor Wear: When not in human attire she wears... paint.
- Victoria's Secret Compartment: Despite having a smaller bust size than Nyarko.
- Wrong Genre Savvy: In Episode 7, after Cuuko laments that no game console may replace the Xoth-731, Mahiro comforts her, telling her that someday something that can fill the void left by Xoth-731 will come her way. Cuuko thanks him, but tells him not to try setting up an Event Flag with her; Mahiro plays along.Mahiro: "Don't worry about that. Should a flag come up, I would break it immediately."
- Yandere: Subverted. After hearing Nyarko loves Mahiro, the first Cuuko does is swearing she will kill him. After she understands Mahiro is not happy to have Nyarko all over him, Cuuko never tries to hurt him and is rather pleased that he wants her help to get Nyarko off his back.
Hasta
Voiced by: Rie Kugimiya (Japanese), Tomokazu Seki (Japanese, alternate form), Alejandra Delint (Latin American Spanish)
A young boy with long blond hair, who happens to be the humanized version of Hastur, the Unspeakable One, godde... deity of wind, depicted here more as the benign deity of shepherds than the Rapine Storm version. He is also the son of the president of Carcosa Computer Entertainment (CCE), a famous video game developer.
- Agent Peacock: He looks really girly and has an obvious crush on Mahiro, yet he holds himself in battle very well.
- Ambiguously Bi: In Volume 7, he admits that he feels warm and fuzzy around Luhy as much as he does with Mahiro, though he doesn't really understand anything further than that.
- Badass Adorable: See this incredibly cute little boy? He can also hold himself in battle.
- Because You Were Nice to Me: Hasta fell in love with Mahiro after the latter bumped into him and helped him get up.
- Beware the Nice Ones: He is the nicest guy in the cast, but he is also a capable fighter.
- Blow You Away: He fights by creating strong wind, vacuum blades, or forming nearby vacuum areas around enemies.
- Camp Gay: He's less flamboyant than most stereotypical gay guys, but fairly effeminate to fall into this trope rather than Straight Gay.
- Color Motif: He has long blond hair and his casual clothes and outfit of his Super Mode are all yellow. Likely a reference to both Hastur's depiction in "Haita The Shepard" (as a Benevolent God) and "The King in Yellow" and Lovecraft's stories (as well... The King in Yellow)
- The Cutie: He's the most adorable and huggable of the aliens. His sweet temper is also why he's the only one who Mahiro always tolerates.
- Dude Looks Like a Lady: Because of Hasta's cute face and long hair, Mahiro thought he was a girl until Nyarko called him "Hasta-kun".
- Gay Option: Hasta is the only boy in Mahiro's harem, although he still looks and acts like a girl.
- Hair Antennae: A couple of cowlicks.
- Hair of Gold, Heart of Gold: The nicest of the aliens and the only one with blond hair.
- Incompatible Orientation: No matter how much Hasta loves Mahiro and how girly he might be, Mahiro won't fall in love with another boy.
- Innocent Blue Eyes: He has big light blue eyes to match his sweet personality.
- In the Hood: Hastur, as the King, is often portrayed in artwork as being hooded. This is referenced visually by having Hasta wear a hoodie.
- Long-Haired Pretty Boy: He has a pretty face and long blond hair tied into a side plait.
- Lovable Sex Maniac: He's more subdued than Nyaruko and Cuuko, but he isn't shy to talk about how much he wants to "combine" with Mahiro.
- Moe Anthropomorphism: The most common Mythos depiction of Hastur looks like a masked man, clothed in yellow rags, often with tentacles slipping through its hem. Here, Hasta is a cute little boy who looks like a cute little girl.
- The Mole: Outright tells Mahiro that he was sent by his father to gather data on Earth's entertainment from his mother Yoriko on behalf of the CCE, but decides to stay instead after the mission is called off.
- Nice Guy: By far the nicest of Mahiro's alien housemates and the one least likely to get him annoyed.
- The Nose Knows: Has shown the ability to smell people from long distances.
- Older Alter Ego: His Super Mode is much taller and much more mature sounding.
- Older Than He Looks: Despite his youthful looks and shortness, he's the same age as Nyarko and Cuuko, letting him attend Mahiro's Boryo Municipal High School.
- Only Sane Man: Between Nyarko and Cuuko's squabbles, back in space grade school, he used to act as their middleman.
- Pinky Swear: Hasta suggests it to seal Mahiro's promise to consider his love confession again... in 25 million years.
- Power Makes Your Hair Grow: His hair is much longer in his Super Mode.
- Scenery Censor: Happens in the Beach Episode of season 2 when the water constantly flows to censor his chest.
- Student Council President: During his, Nyarko and Cuuko's space elementary school days.
- Super Mode: His "King in Yellow Form", first seen in episode 3 of Nyarko-San W and voiced by Tomokazu Seki.
- Super-Powered Alter Ego: His "King in Yellow Form" talks like he and regular Hasta were different people.
- Tender Tears: Following the tradition of Rie Kugimiya's characters, poor kid leaves the cafeteria crying in Episode 7, thinking Nyarko is pregnant with Mahiro's child.
- Token Mini-Moe: Hasta is the shortest member of the main cast and looks like an adorable preteen girl despite being a boy and about the same age as Nyarko and Cuuko.
- The Twink: Blonde, looks really young, positively gay for Mahiro.
- Whole Costume Reference: The bandage-looking outfit he wears in "King in Yellow Form" is based on what T.M.Revolution wore in the music video and single cover for his song "Hot Limit".
Shantak-kun
Voiced by: Tomoko Kaneda (drama CD and first anime) and Satomi Arai (second and third anime)
Nyarko's pet, a female shantak (avian with horse's head and bat wings).
- Expy: A Mix-and-Match Critter that likes carrots and can change into a spaceship or a girl.
- Godiva Hair: When she first turns into a human, she naturally has no clothes on. Her hair covers anything important.
- Head Pet: Is seen riding atop Yoriko's head a couple of times.
- Humanity Ensues: Briefly in the seventh volume/episode 8 of season 2 thanks to Cuuko.
- Involuntary Shapeshifting: Nyarko can Final Form Ride Shantak-kun into a Cool Bike or a spaceship (which is how she came to Earth in the first place).
- Pet Monstrosity: Before it got one-shotted by a Nightgaunt on Episode 1 of the second anime.
- Ridiculously Cute Critter: Lampshaded by Nyarko in episode 1 after it gets defeated by a Nightgaunt: "They say the weaker they are, the cuter they are!"
- Sleep-Mode Size: Spends most of her time like this recovering/conserving energy, only changing into her full-size form on the rare occasions when they need her.
Luhy Distone
Voiced by: Mariko Kouda
A green-haired woman and employee of Cthulhu Corporation, a rival video game developer to CCE (run by Hasta's father). She's also the humanized version of a Cthulhi, the star-spawn of Cthulhu himself and the closest thing to the Big C to appear in the series to date.
- Big Damn Heroes: Pulls this in episode 12 to help everyone fight off Roy Fogger the Lloiger.
- Cool Car: The Delorean. Yes, THE Delorean.
- Fallen-on-Hard-Times Job: From game console developer to takoyaki vendor and a Magical Girl actress... isn't it sad, Luhy?
- Heel–Face Turn: After Episode 6, she bounces back from her Villainous Breakdown and tells everyone she has no hard feelings, and she even helps Mahiro escape the cursed dating sim in Episode 8.
- Hot for Student: She becomes a teacher for Mahiro's class, and has feelings for Hasta who is one of her students.
- Hot Teacher: She's the hottest woman in the cast and becomes a teacher late in the light novels.
- Humiliation Conga: Yoriko warns her that Xoth-731 is too high-end and thus too expensive for commercial release, gets a call from her CEO telling her that she (and her entire department) had been laid off, and had to watch Cuuko reluctantly destroy Xoth-731 after it caused Deep Ones to be brainwashed by a Zombie Apocalypse game currently uploaded into the system... poor lady.
- An Ice Person: She uses ice attacks against some mooks during the final battle in Episode 12.
- Ma'am Shock: When Mahiro ran by asking for help, Luhy seemed willing to help...until the cute little girl clinging to his back called her "obaa-chan". For that, she instantly ratted the pair out to Nyarko.
- And again in "How to Defeat a Kind Enemy", where Nyarko snarkily calls Luhy a 30-year-old, which causes her to ice up the room and angrily declare that even if you round her age, she's still in her 20s.
- Magical Girl: She performs as one in one of her jobs.
- Moe Anthropomorphism: She's a member of the Cthulhi race, the spawn/servants of Cthulhu himself. Cthulhu is a pulpy green humanoid monstrosity with a tentacled head and wings. Contrast that with this smoking-hot lady.
- Ms. Fanservice: Everything about her, from her glasses to her business suit, is attractive.
- Navel-Deep Neckline: Her business suit is really low cut, just barely reaching her midsection.
- Nice Girl: Post Heel–Face Turn, she is really one of the more consistently helpful and kindhearted characters in the series.
- Nothing Personal: When she runs into the cast after the Xoth incident, she's quick to insist that the only reason they were enemies is because of her old job with the Cthulhu Corporation and that she wants to bury the hatchet — especially with Hasta, since she thought he was an industrial spy and was therefore harsher towards him than everyone else.
- The Rival: She declares Mahiro one in the light novels after she realizes she has feelings for Hasta.
- Villainous Breakdown: Played for Laughs in Episode 6. Upon learning that Cthulhu Corp. is ditching its gaming department, she stoops in defeat with Dull Eyes of Unhappiness before she breaks down Laughing Mad in a desperate attempt to complete Xoth-731 before her superiors pull the plug on the project once and for all.
Yoriko Yasaka
Voiced by: Kikuko Inoue (drama CD and first anime) and Aya Hisakawa (second anime)
Mahiro's mother and a part-time monster hunter.
- Action Mom: Works as a part-time demon hunter (her introduction in Episode 4 even makes some Shout Outs to Monster Hunter).
- Admiring the Abomination: To an extent. While her son is somewhat freaked out and disturbed by Nyarko and Cuuko, she is more than happy to call some of their antics adorable, though she also makes it clear she will not hesitate to berate them should they cross her.
- Affectionate Nickname: Always calls Mahiro "Hiro-kun"; while pretending to be even fluffier during the Dating Sim episode, she went with "Mahiro-chan".
- Alliterative Name: Yoriko Yasaka
- Ascended Fangirl: Just like her son, but unlike him she readily welcomes Nyarko, Cuuko and Hasta into their household.
- Badass Adorable: In bright-and-sunny attitude and youthful appearance, Yoriko can easily be mistaken for for Mahiro's cute big sister.
- Cuddle Bug: Frequently embraces her son upon returning from her adventures, supposedly to recharge her "sononium".
- During the Trapped in TV Land episode, she pretends her personality's been "rewritten" as an excuse to be even snugglier towards Mahiro; when he says "Knock it off Mom, I know you're just faking it," she's quite disappointed.
- Gamer Chick: Collector of consoles of all sorts.
- Happily Married: At the start of the second series, she's in the middle of her seventeenth honeymoon. While this might seem like a cover for her monster-hunting, Yoriko confirms that her husband is fully aware of her work, and that his being so supportive is part of the reason she loves him so much (while blushing).
- Harem Nanny: Being the male protagonist's mother, she watches over him and his Unwanted Harem of aliens that move into their house.
- Improbable Weapon User: Just like her son, she uses forks as her main weapon.
- It Runs on Nonsensoleum: She claims that she needs to cuddle Mahiro because it produces a substance called "Sononium" ("Musukonium" in Japanese) which she needs to function properly; if she doesn't get her daily dose she becomes depressed and lethargic.
- Mama Bear: Eased off on this after her initial meeting with Nyarko and Cuuko, especially after they explained themselves, but both are now conscientious enough to keep within Yoriko's good graces.
- More Dakka: Mahiro's fork = good. Yoriko's eight forks = better (in episode four when she is first getting ready to go after the aliens she's actually packing a total of ten ready to fly, five from each hand).
- Mum Looks Like a Sister: Compare how she looks next to Mahiro◊ and tell us that she doesn't look like she would possibly be his older sister.
- Noodle Incident: In the light novels, it's revealed that Yoriko has apparently crossed paths with Atlach-Nacha (Atoko) in the past, and whatever happened between them resulted in Atoko utterly despising Yoriko.
- Older Than She Looks: Just looking at her, you would never believe she had a 17-year-old son.
- Made more blatant in the second season, when she flashes back to the day her husband proposed; the only noticeable difference between then and now is the way she wears her hair.
- Overprotective Mom: Has minor elements of this, especially in her first appearance where she makes it very clear that she won't tolerate any untowards behavior directed at her Hiro-kun.
- Parental Incest: Not normally, but thanks to an alien love potion in episode 11 of Nyarko-San W, she starts leaning that way.
- Shipper on Deck: After warming up to Nyarko, Yoriko doesn't just give her approval for her and Mahiro to date, but seems to be gently nudging them towards each other. Particularly in episode 7 of the second TV series, where she convinces Mahiro to take Nyarko on a date to apologize for his Heroic BSoD-inducing Brutal Honesty, then makes sure Cuuko and Hasta don't interfere.
- Speaks Fluent Animal: She seems to be the only other character besides Nyarko that can understand what Shantak is saying.
Tamao Kurei
Voiced by: Yōko Hikasa (Flash series) and Yuka Ootsubo (Anime series)
A classmate of Mahiro, Nyarko, Cuuko and Hasta, who is always on the prowl for the hottest news in school.
- Dark Horse Victory: She discusses this in the the Trapped in TV Land episode, pulling Mahiro into a secluded closet while Nyarko, Cuuko, and Hasta are busy fighting over him. However, she quickly lies and says that she was just joking, since as noted below she's fine with letting Nyarko have him.
- Foreshadowing: Her body was temporarily taken over by Isuka, a Yithian. Yithians have megaphone-shaped appendages.
- Genki Girl: Not as pronounced as Nyarko, but she definitely shows a lot of zeal with her hobby.
- Grand Theft Me: Throughout Episodes 9-10, courtesy of Isuka, a Yithian who wanted to alert Nyarko of her extremist kin's plans.
- I Want My Beloved to Be Happy: She has feelings for Mahiro, but because she feels she cannot compete with Nyarko (and considers her a good friend), Tamao steps aside and becomes a Shipper on Deck.
- Iconic Item: Megaphones. They are even the principal design of her ribbons.
- In-Series Nickname: "Walking Speaker"
- Matchmaker Crush: She works to get Mahiro and Nyarko together pretty much from Day 1, ignoring her own feelings for him.
- Unwitting Instigator of Doom: While doom may be an overstatement, Tamao always pushes Nyarko to be aggressive in her pursuit of Mahiro. Which only pushes him away.
- Wistful Amnesia: Isuka thought she already erased Tamao's memories of her body being used by the Yithian. She actually remembers most details of their interaction, and decides to become her friend.
Takehiko Yoichi
Voiced by: Yoshihisa Kawahara (Flash series) and Wataru Hatano (Anime series)
Mahiro's best friend and confidant.
- The Ace: Episode 4 of Nyarko-San W shows him bowling three perfect games in a row, and then doing the same with 9-Ball. This is implied in the same episode as being the result of Isurugi, the yithian, sending him "happiness waves" from the distant future in an attempt to make up for possessing his body.
- Gay Option: In the dating sim episode 8, it's suggested that he might confess his feelings for Mahiro if the latter fails to pick a love interest by the end of the game.
- Grand Theft Me: In Episodes 9-10, courtesy of Isurugi, a rogue Yithian attempting to pull a grander version of this trope upon the rest of humanity to acquire their entertainment. He willingly leaves Yoichi after pulling off a Heel–Face Turn.
- Only Sane Man: Besides Mahiro, he is the most level-headed of the cast... though on occasion he would join their antics.
- Welcome to Corneria: Gets stuck doing this in the Trapped in TV Land episode, which makes for a pretty funny image when Mahiro grabs his shoulders and shakes him, all with a text box, which none of the other's have, hovering in mid-air between them.
Isuka
Voiced by: Satomi Arai
A Yithian.
- Chekhov's Gunman: Plays a major role in a later novel, where she helps Mahiro go back in time to save Nyarko and Cuuko from being Ret Gone'd by a bitter classmate.
- Friendship Moment: Tamao befriends her even after Isuka had to leave her body after the former wakes up in midnight to see Isuka trying to finish a game.
- Grand Theft Me: Like all Yithians, she can steal a human's body in her case, Tamao.
- My Species Doth Protest Too Much: Isuka came to Earth to warn Nyarko of a group of extremist Yithians intending to pull off a massive Grand Theft Me upon humanity to take over their entertainment.
- Spell My Name With An S: Is it Isuka or Yithka?
Isurugi
Voiced by: Wataru Hatano
A rogue Yithian and member of an extremist faction of Yithians who intend to pull off a massive Grand Theft Me upon humanity.
- Defector from Decadence: Upon realizing that their boss is actually using the extremists for his puritanical campaign.
- Grand Theft Me: Like all Yithians, though in his case, he wants to pull off a massive version of this trope upon humanity to obtain all their forms of entertainment. Unfortunately, his faction's boss turns out to be a Space Moral Guardian.
- Well-Intentioned Extremist: He just wants to take over humanity's entertainment. Too bad his faction's boss had other ideas.
Ato-ko Shirogane
Voiced by: Azusa Kataoka (now Azusa Enoki)
A beautiful woman in a kimono who comes to Mahiro's house in Remember my Love(craft-sensei), and plays a much larger (and more sinister) role in later novels. She's also the humanized form of Atlach-Nacha, the Spinner in Darkness.
- Aloof Dark-Haired Girl: Played with. She appears to be aloof, but is really a Covert Pervert.
- Canon Immigrant:
- In the original Mythos, Atlach-Nacha lacked any connotation of being promiscuous. Thanks to a certain game, this attribute was given to the Great Old One in Japan.
- Ato-ko herself first appears in Remember my Love(craft-sensei). The novels only briefly mentioned her as a certain being with a grudge against Yoriko, until her actual appearance in volume 10.
- Cluster Bleep-Bomb: Her discussion with Cuuko is almost totally bleeped out. Whatever was said, it embarrasses even Cuuko.
- Covert Pervert: Once her gentle facade is taken off, she's quite the pervert of a level that mortifies even Cuuko.
- Expy: Looks like Hirasaka Hatsune in a kimono from Atlach=Nacha (Ato-ko's namesake). Interestingly, Shirogane is also the name of the antagonist in that Visual Novel.
- Foreshadowing: Her only "appearance" in the two regular series is in Nyarko-San W episode 11, where she sent Nyarko a box of chocolates... which turn out to be laced with a Love Potion, suggesting that she's attempting to set Mahiro and Nyarko up for her inevitable boyfriend-theft attempt.
- Humanoid Abomination: Basically a Giant Spider with a quasi-human face.
- The Internet Is for Porn: She asks Mahiro to help her find a picture of a dog she saw online earlier. When Mahiro opens up her browser history, it's nothing but porn (and judging by the timestamps, she was browsing a large number of sites at the same time). For that matter, her desktop image is a salacious image of herself.
- Moe Anthropomorphism: Of Atlach-Nacha.
- My Sensors Indicate You Want to Tap That: She can smell people's love for one another, which she uses to pick out the best moment to steal a guy from another woman. She also confirms that, despite Mahiro's fervent denial, he really does like Nyarko.
- Noodle Incident: In the light novels, it's revealed that Atoko utterly despises Yoriko because of some incident in the past where they crossed paths. Thus, her pursuit of Mahiro might have a minor revenge element to it as well.
- Relationship Sabotage: This is more or less her hobby.
- Weak, but Skilled: According to Nyarko, she's not amazingly powerful but is still a tough opponent because her attacks (webbing and poison) are hard to deal with.
- Yamato Nadeshiko: Looks the part, but not the attitude.
Nyarue
Voiced by: Sayuri Hara
Another Nyarlathotepian and Nyarko's cousin. Appears in Remember my Love(craft-sensei).
- Canon Foreigner: Exclusive to Remember my Love(craft-sensei)
- Eldritch Abomination: Her real form, censored to protect the audience's sanity.
- Informed Attribute: Nyarko says that she carries a bat because she's athletic, but the only time we see her wield it is in the ending credits. Most of the time she just flails around in a panic.
- Passionate Sports Girl: Being more interested in sports, she always carries a bat around with her.
- Shapeshifter Identity Crisis: Has a tendency to return to her true form when embarrassed.
Nodens
Voiced by: Bin Shimada
A space smuggler who intended to abduct Mahiro as a subject of space Boys' Love Genre shows.
- Identical Stranger: The different Nodens...es?; lampshaded in episode 12 of Nyarko-San W where the Nodens working for the PDO says that he's apparently got the kind of face that people find familiar.
- Inexplicably Identical Individuals: In the last episode of Nyarko-San W, Mahiro is surprised and pissed off to find Nodens working for the PDO, but they're told there are actually multiple Nodens...ies?, and this one isn't the same as the one who tried to sell Mahiro as the star of a Boys' Love show.
- Though the "good" Nodens does immediately remark that Mahiro has the right look for that kind of work, and immediately gets chastized.
- Kaiju: His act on a children's stage show on Episode 9, opposing Luhy as a Magical Girl.
Nyar-o
Voiced by: Daisuke Hirakawa (Flash series) and Takeshi Kusao (Anime series)
Nyarko's older, dumber brother.
- Book Dumb: So dumb he dropped out of a C-list college, whereas Nyarko became the best of her class at a top university.
- Cosmic Plaything: Not even Mahiro got to meet him!
- Freudian Excuse: Blames a childhood incident where Nyarko accidentally hit him on the head during a game of space baseball for becoming Book Dumb.
- Harmless Villain: In the anime, getting hit in the toe by Nyarko's motorcycle makes him A Twinkle in the Sky; subverted in the light novel, where he survives that and comes back to put up a decent fight, but still gets his ass kicked.
- Shock and Awe: Only in the light novel. His Howler in the Dark form use lightning balls as a weapon.
Cuune
Voiced by: Ryōka Yuzuki
Cuuko's cousin, who harbors a huge crush on her.
- Childhood Marriage Promise: When they were young, she got Cuuko to say things like "I love cousin Cuune and want to marry her when I grow up" into a tape recorder; as far as she's concerned, that counts as a legally binding marriage contract.
- Clingy Jealous Girl: Does not take it well when Cuuko says she's in love with Mahiro.
- Color Failure: When Cuuko announces her "engagement" to Mahiro.
- Curtains Match the Window: Red eyes to match her red hair.
- Elemental Hair Colors: Like her cousin, she has Playing with Fire powers and is red-haired. She also has red eyes, making them Elemental Eye Colors.
- Gamer Chick: Likes to coax Cuuko into playing video games with her.
- Hopeless Suitor: She just refuses to admit the possibility is all.
- Kissing Cousins: She wants to marry her cousin Cuuko.
- Lovable Sex Maniac: Feels Cuuko up in her introductory scene.
- Mad Love: Just like Cuuko with Nyarko, Cuune tends to be all over Cuuko and just won't leave her alone despite Cuuko obviously not wanting her around.
- Playing with Fire: She has fire powers due to being a Cthugaian like Cuuko.
- Psycho Lesbian: Primarily motivated by her lust for Cuuko, just like how Cuuko behaves around Nyarko. Cuune cannot even fathom the idea that Cuuko might be in love with somebody other than her, and several times during Cuuko's "date" with Mahiro she's half-ready to attack and/or kill him.
- Shout-Out: Her intro has her tell Mahiro "omae wa mo shindeiru". And then she proceeds to use Gratuitous English to say Welcome to this crazy time.
- Signature Headgear: Similar to her cousin, she ties her hair up with a black ribbon that looks like a flame.
- Victoria's Secret Compartment: Which has enough space to store a binder and tape recorder.
Tsuruko
Voiced by: Saki Yamakita
An alien doujinshi artist, who draws manga based on Mahiro after hearing about it from Nyarko. She visits and lives on Earth illegally in the hopes of meeting him someday.
- Affectionate Parody: Of the Yaoi Fangirl archetype, including gladly referring to herself as "rotten" (an insulting nickname for yaoi fans, at least in Japan) and saying her favorite quote is "There's no such thing as a girl who doesn't like homos!"
- Butt-Monkey: Her attempts to meet Mahiro are always thwarted in one way or another.
- Loony Fan: Of Mahiro's; every time she appears, she's plotting out the order in which she's going to shake his hand, get an interview, have him autograph her doujin, etc. It never once occurs to her that he might not enjoy being the "star" of a Boys' Love comic...
- Moe Anthropomorphism: Of Ut'ulls-Hr'ehr, one of the Great Old Ones; one Japanese pronunciation of the name is "Uutsuru Heea" (ウーツル＝ヘーア), from which "Tsuruko" comes.
- Otaku Surrogate: She is obsessed with manga to the point of living on Earth and creating some herself.
- Ship Tease: With Yoichi, who runs into her at least twice. The first time is a Not What It Looks Like moment in episode 4 of season 2 caused by Isurugi, the second in episode 11 with him being under the influence of a Love Potion.
- Yaoi Fan Girl: She is the artist for a yaoi doujinshi featuring Mahiro.
