Monster Girl Encyclopedia

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Imagine your typical RPG-style fantasy world, filled with monsters and adventure.

Now replace all of said monsters with Cute Monster Girls, and throw in huge amounts of Fan Service and outright sex. The Monster Girl Encyclopedia is a bestiary dedicated to cataloging all the different kinds of Cute Monster Girls in the world. The entries are filled with Fetish Fuel, and most are Not Safe for Work.

A compilation of translated entries for the Encyclopedia canon could at one time be found here (the original site needed registration in order to view the contents, which makes the Wayback Machine link mostly usely). New monster species are being added all the time by the original creator , and so the list linked above is not complete yet.[when?] Just go to either Danbooru (NOT SAFE FOR WORK) or Gelbooru for the newest additions to the list ( which may not even be translated into English yet). A new -booru has opened recently[when?] thanks to the Monster Girl Unlimited staff: MonsterGirlbooru WARNING: The -booru sites contain NSFW material! Do not browse with touchy relatives present.

  • Kenkou Kurosu/Cross, the artist's, page can be found here.
  • Monster Girl Unlimited: The Group responsible for creating the English Translated Profiles. Also acts as a Fan Community. Requires registration to view. Now Dead.
  • Monster Girl Redux: A sister fan forum where the translation group and fan community moved after Unlimited died. Also requires registration.
  • Another much-smaller attempt at an Encyclopedia from apparently the same artist as the Living with Monster Girls series.
  • An alternate site is here
  • And now, we have an actual Monster Girl Encyclopedia Wiki

Also see Living with Monster Girl for a Doujinshi series with similar content.

Tropes used in Monster Girl Encyclopedia include:
  • Abuse Is Okay When It Is Female On Male: The Ogre is described as literally beating her partner into submission so she can carry him off in the first place, then beating him while having sex with him, and beating him even harder if he tries to fight back, though, as the profile describes them as pleasurable, it is uncertain whether "beating" is a metaphor for rough, passionate sex.
    • The Dark Elf, meanwhile, is clearly designed to appeal to the BDSM fetish and is noted as referring to her partners as "slaves". The setting is rather ambiguous about the details of this, though, and so there is quite a bit of debate as to what this involves (for example, is she an actual sadist?) and just how bad she is about doing what she does do.
  • Arcadia: Bright Green Demon Realms look like this on surface, looking almost the same as a normal uncorrupted area, retaining the ability for normal plant life to grow there and being more relaxed than a Dark Demon Realm, but the truth is that only monsters and incubi find such places peaceful. The Demonic energy in the air is only slightly less thick than it is in a Dark Demon Realm and plenty of Order heroes and adventurers have wandered into such places without realizing what they were and ended up monsterized as a result. That said, the soil is also richer than in a normal land, making it even more ideal for growing crops than most uncorrupted lands so Saphirette certainly saw turning her home country into one as worthwhile.
  • A Date With Rosie Palms: The Roper, a parasite that causes its host to sprout Naughty Tentacles, lures in mates by stimulating the host's genitals, causing said host to emit noises that lure in their targets.
    • It is also said that if a colony of Devil Bugs cannot find a male victim, they'll resort to this. So far, nothing has suggested other mamono do it.
    • Merrows enjoy watching other couples, and will even trade their blood in exchange for saucy stories to stimulate themselves with later.
    • Raiju are constantly masturbating, which charges their electrical powers.
  • A Form You Are Comfortable With: Doppelgangers. They are shape-shifting spirits formed out of unrequited love, and turn into an idealized version of the woman their lonely male targets pine for. Subverted in that their true forms, short, flat girls in black dresses, are hardly maddening or awful.
  • Action Survivor: More like Sexual Survivor. The in-universe author of the encyclopedia managed to get deep into the Demon Lord's Castle and have an interview with her, and has encountered every monster present in the book. Sometimes he got attacked, but always "survived" (or at least, none have kept him as their husband) and continued working on the book. At the end of compilation book foreword, he notes that The Order is hunting him now so he's running to Zipangu. Since every entry after Lilim (the final entry in compilation book) are Youkai, it's obvious that he made it (even he did end up having to make a detour to Polove where he wrote Demon Realm Traveler's Guide with Saphirette's help). Of course, since he's writing an encyclopedia and working to correct peoples misunderstandings toward monsters, the Demon Lord is most likely assisting him. It's also implied that he's mostly been interviewing monster girls who already have husbands and he mentions offhandedly in the second volume that he has a monster girl "traveling companion" who is either actually his wife or aiming to become such. Still he does mention that he's been attacked a few times regardless and his "traveling companion" is a Leanan Sidhe, which isn't really the strongest monster girl out there.
  • Alchemic Elementals: All four of them are featured as monster girls, though the Salamander is replaced by Ignis. It was later added to the encyclopedia as a subspecies of the Lizardman race.
  • All Chinese People Know Kung Fu: The Hinezumi, from the Mist Continent, are said to "excel at martial arts". Likewise, the Ren Xiongmao are said to be good at using a Bo staff in martial arts.
  • All Women Are Lustful: Best case scenario. Some are not so much lustful as they are hungry.
  • Alice Allusion: For one, there's Alice-type succubi, the artwork for Wererabbit also has her carries a large pocket watch. There's even a bit of dialogue in the book about this, including a portion of the world called Wonderland.
    • In addition, the Alice emits a pheromone that makes men rape her, forcibly turning them into Lolicons. This, and her appearance as a young girl, is possibly a reference to rumors of Lewis Carroll being a Lolicon himself, to one degree or another.
    • Wererabbits can teleport their husbands to the Wonderland.
    • There are now several monsters based upon Alice in Wonderland characters, such as the Mad Hatter, March Hare, Dormouse...
    • The Alice likes to chase after and play with Wererabbits.
  • All Amazons Want Hercules:
    • Orc and Ogre are usually abusive toward their male slaves, but beat one in combat or during sex and she will become an obedient wife/slave herself. More pronounced with the Orc than with the Ogre.
    • Dragons have a tsun-attitude toward their husbands at first, treating them as precious treasures and refusing to let them out of their sight. They become full dere when they recognize the man as an "Alpha male," and become subservient to him.
    • Lizardmen, Proud Warrior Race Gals all, will propose marriage to whoever beats them in a duel. And they won't give up even if the man refuses at first, following him around and waiting for him to change his mind. Salamanders are much the same, just more Hot Blooded about it.
    • Baphomet, the most powerful demon-beasts, turn men into Lolicons regardless of their strength, but will often only accept those who beat her in combat as husbands. Although apparently they are willing to go for a weaker man if he shows enough persistence to impress them that way.
    • Averted by the Amazoness though. In their worldview, men are supposed to Stay In The Kitchen and only come out to be publicly raped by their horny "wives".
    • Echidna are noted to specifically prefer heroes as husbands and create trap filled dungeons that they wait at the bottom of in the hope that a strong enough hero will reach them and prove himself worthy of becoming her husband.
    • A bit complicated in practice, however. As explained in World Guide 3, monsters do in general consider Heroes (i.e. humans who have through various means surpassed normal human limits) to be ideal mates, the "best" males, etc. However, monsters almost always prioritize an existing relationship above this. That is if they had to choose between the "best" male and a male they already knew and were fond of, they would choose the man they were already fond of, and train him into being the "best" male for them. Since monsters can, by turning men into incubi, enable any man to surpass normal human limits, they need not be restricted if they have a preference for men of superior ability. Its also possible to win over a monster's heart through sheer persistence, as many baphomets fall in love with men who challenge them to fights again and again, despite such men being unremarkable in ability.
  • A Man Is Not a Virgin: Almost certainly not in this world. If he does subvert it, he'll have horny Unicorns trying to get him to become their husband.
  • Amazonian Beauty: The Minotauri and Jinko are ripped, but like pretty much all monsters are still attractive.
  • Ancient Egypt: Represented by Anubi, Sphinxes, Khepri, Apophis, Pharao and Mummies.
  • And I Must Scream: Some of the monsters do this:
    • Most plant type monsters will constantly keep their husband bound by vines or even turn them into part of the tree they reside in.
    • Monsters who worship the Fallen God will kidnap men and take them to Pandemonium where time is eternally still.
    • The Mimics, Jinns of the Jar and Charybdis lure men towards their hiding spot, and then suck them in an alternate dimension where they can be trapped forever.
  • Angelic Beauty: Applies to the Angel and all of her subspecies: the Valkyrie, the Houri and the Cupid.
  • Animate Inanimate Object: In a sense, both the Chochin-Obake (a lantern) and the Karakasa-Obake (an umbrella), due to being based on the tsukumogami. And also the Living Doll.
  • Anime Chinese Girl: The Hinezumi and the Ren Xiongmao. And probably all other monsters from the Mist Continent.
  • Anything That Moves: It's mentioned that zombies can't distinguish a man from a woman, and so they'll pretty much violate both indiscriminately.
  • The Archer: The Elf and Centaur are both drawn wielding a bow and arrow.
  • Art Evolution: There's quite a difference between the earliest entries and the newest, and quite a few versions have actually been redone graphically, sometimes with very visible changes (the Lizardman, for example, lost a few inches, got more detailed armor, had her hands changed into more bestial claws, and... gained quite a few inches back).
  • The Assimilator: Dryads; any man they catch will eventually fuse permanently with their tree, only able to die once the tree eventually dies.
    • Also the Matango. Their spores enter men's bodies and start changing their behavior, and once they (due to the spores) have sex with a Matango, they will turn into a Mushroom man themselves.
  • Atlantis Is Boring: Averted. Aquatic monsters are often just as lustful as those on land. And Sea Bishops can transform any man so he can live in ocean freely, though they only do this to either aquatic monster's husbands or drowning men with no other chance of survival.
  • Author Appeal: The artist seems to love Horny Devils, considering how many monsters have been corrupted by them. And let's not forget the number of monsters that convert other women into their species, or the number that can be turned into more submissive versions...
    • And the fact most of them want to rape you.
    • Pretty much all monsters without animal ears of some sort have pointy ears, presumably due to this reason.
  • Bee People: The Honeybees.
  • Belly Dancer: The Aspara fits the archetype to a T. Genies also wear the outfit as per the usual for female genies in fiction, though theirs is far more Stripperiffic than average, consisting of strapless panties and legwarmers rather than actual pants.
  • Better Than Sex: Fully Averted. There is nothing Monsters like to experience more than sex, albeit there are still many things they like to do, being interested in pleasure and fun in general and many like to have variety along with their favorite thing of all.
  • Beware the Nice Ones: Jurogumo appear sweet and harmless during the day, but at night turn into sadistic rapists which will almost invariably breaks their husbands' wills eventually.
  • Big Brother Attraction: A subversion. Though they're not related at all (usually), the lolis of the Sabbath all refer to their male partners as "Big Brother". This is probably just for cuteness value.
  • Bigfoot, Sasquatch and Yeti: The Yeti monstergirl. Here, they are very friendly creatures that love giving hugs to anybody. They save frozen travelers by heating them with their own high body temperature, and if a man were to hug them back, they would see it as the man courting them.
  • Bizarre Sexual Dimorphism: The end result of the Demon Lords plan would mean that humans and monstergirls are a single species with humans (including male elves and dwarves as types of humans) as men and all the various monster girl races as women.
  • Blessed With Suck:
    • You're a man in a magical land full of Cute Monster Girls which, presuming they find you attractive, are all willing and eager to have sex with you? Sounds fun, except some of them can be less then attractive unless you're into the fetish they represent, many of them aren't very big on the concept of "No", and pretty much all of them are very possessive. But, then again, rape is okay when it's female on male.
      • Plus, if you happen to have an abundance of spiritual energy, you're probably an extremely powerful person or a mighty wizard... and you're going to draw eager, hungry monsters like iron fillings to a magnet, regardless of your attraction to them or desire to attract them.
      • More recent supplementary materials have worked to mitigate some of these issues. Sabbath Grimoire introduced Mana Markers, which among other uses can be used by men who are interested in a particular species of monster girl to indicate that interest to other monster girls so that any monster not of that species will leave you alone.
    • If you're a woman in this world, you can be turned into a Cute Monster Girl, gaining supernatural charm and beauty (along with other abilities). Unfortunately, not all of the potential transformations you can undergo are necessarily attractive to you (Roper and Dark Slime particularly), your personality changes when you are transformed (though there's a bit of a Broken Base on exactly how much is changed; see Draco in Leather Pants in the YMMV page) and, worst of all? Most of the monsters won't ask your permission first.
  • Blob Monster: The Slimes and all their variants. They're essentially living goop that takes on the proportions of an attractive woman. They tend to be not very smart, and if their mass increases too much, they'll split of part of themselves as a new Slime.
  • Blood Knight: The Salamander. She doesn't care really if a man wins or lose when he fights her. So long as he can give her the most enjoyable fight possible and prove to be her most Worthy Opponent, she'll follow him to the ends of the earth, publicly declaring her love for him, until he agrees to be her husband.
  • Blue Eyes: The Yuki-Onna has a stunning pair.
  • Blue and Orange Morality: The monstergirls have different standards than humans, but from their own perspective aren't evil at all. To them, sex is as important as feeding (which for some is the same thing), likewise to them Sex Equals Love, so they don't see anything wrong with raping a man they like. Especially since they still have the mindset of a predator, and tend to see human males as prey. Though there are a few who respect it if their husband is not in the mood. They are also hedonists who happen to be extremely depraved to the point where they don't condemn incest; so a monster child raping her father is not frowned upon, and often encouraged. Likewise, to them physical appearance doesn't matter, they only care if the man they seek is a decent person and has attractive spirit energy. However, they do (most of them at least) love their husband immensely and would never dream of leaving him and consider murder something unthinkable.
  • Bodyguard Babes: the Kunoichi are this to their husbands, as are soldier beetles and some other disciplined, protective monsters.
  • Body Horror: The Roper. A human woman infected with a parasite that causes her lower body to turn partly into slime and sprout long, pink tentacles. At least once the process is over the woman regains control over her body and can maintain a human appearance if she wishes to.
  • Breast Expansion: The Holstaurs have the power to adjust the size of their chests at will.
    • From Fallen Maidens, this is usually happens when girls are converted into monsters.
  • Brought Down to Normal: If a doppelganger's husband see her true form, and love her as she is, she will lose her shape-shifting ability, since she can't be herself with it. Not that she'd need it anymore.
  • But We Used a Condom: Word Of God says that the monsters will end up poking holes in your condoms, or outright refuse to use them.
  • Came Back Wrong: Even the dead aren't safe from demonic energy. Their souls can be corrupted and become Cute Ghost Girls, while their bodies can be revived as ghouls, zombies or skeletons.
  • Career Killers: A subversion with the Mantis. They don't kill for money, but they are highly efficient hunters, nicknamed "Assassins of the Forest". A fellow arthropod monster, the scorpion girl Girtablilu, are nicknamed "The Assassin of the Desert" for similar reasons.
  • Cat Girl: The Werecat monster. Giving her catnip results in her raping you. Also comes in Ancient Egypt flavour with the Sphinx, Japanese flavour with the Nekomata and outright Furry with the Cait Sith.
  • Charm Person: All monster girls are this to some degree, as is anyone else who uses Nemphomancy, the succubus created magical discipline that's all about using magic to enhance your ability to seduce a target through making them more aware of the caster's attractiveness or inducing pleasure in the target. Nemphomancy is only truly effective for a person who is already physically attractive though. The Alice seems to have a more unconscious version of this.
  • Chest Monster: The Mimic and Jinn of the Jar are Cute Monster Girl embodiments of this. They pretend to be, respectively, a chest or a large pot, hiding in a pocket dimension within, but any man who messes with it is promptly "attacked". The Mimic pops out and uses magic to get the man to have sex with her, taking him back into the chest if she really likes him, while the Jinn of the Jar sucks him into the pot where her body unconsciously drive the man to have sex with her. Stick something into the Mimic's keyhole, or toss something into the Jinn's jar, and they'll leap out of their home and be helpless. Likewise, you can also just break the Jinn's jar, though this will leave them severely distressed.
  • Children Are Innocent: Subverted. Many of the monster girls at least look like children and even act child-like to some degree. The two biggest subversions would have to be the Alice and the Charybdis. The Alice subconsciously broadcasts a Charm Person spell that eventually Mind Rapes a man into raping her and becoming obsessed with following her as her lover. The Charbydis is the only monster girl to actively have gangbangs.
    • Double subverted by Alice, as her mind will remain innocent as her memory will get reset after the sexual encounter.
    • There is in fact an entire section of the Demon Lord Army filled with nothing but little girls, the Sabbath, whose motto is "To spread the charm and depravity of little girls!"
      • The Sabbath Grimoire reveals that subverting this trope is completely deliberate for several pragmatic reasons on their part. The smaller body of a child is more convenient for casting powerful magic, but even more importantly, it's revealed that the Sabbath's power quite literally comes from committing acts of depravity (like having sex with adults in the body of a child) and going against the teachings of the Order of the Chief God (which expressly forbids that and has a rather dim view of having sex for pleasure in general). They used to be far worse before the current Demon Lord came to power.
    • For a while, it looked like human children were off-limits at the very least. The artist never singled them out when it involved corruption, and even witches were believed to always lolified adults. This was until the Fallen Maidens book introduced a pair of corrupted orphan girls...
    • Seven Seas translates most of the MGE material faithfully, making an exception only when it comes to most implications regarding sexual behavior with the underage. Information on the Sabbath, for instance, refers to the members as petite rather than looking like children.
  • Childhood Friend Romance: Invoked by both the Yuki-Onna and the Kappa. Both tend to go into human villages as children and play with the human children they find there and whoever they liked best of the human children they meet this way will be the one they target as their future husband when they grow up. The Kappa specifically goes after whichever boy she had the most fun sumo wrestling with.
  • The Chosen Many: Heroes in this setting are generally only called this if they were chosen by the Chief God and given special powers to make them more suited to fighting monsters. It used to be there was only one Chosen One at a time, the last of these having been the demon lord's husband, who the order sees as a Fallen Hero. Nowadays with the situation being the way it is, there are a lot of Heroes running around. While they're much stronger both physically and magically than a normal human and have access to special hieromancy spells only they can use that can likewise boost the abilities of any adventuring party or army they chose to fight with, this also makes male Heroes highly desired as husbands by most monster girls and it's also possible for a newly monsterized female hero to turn those support abilities against her former teammates in order to monsterize them too. According to Sabbath Grimoire, Incubi are Not So Different from Heroes, aside from those extra spells, because being awakened as a Hero merely takes off the Power Limiter that the Chief God placed on all humans, which becoming an incubus through having a lot of sex with a monster girl also does.
  • The Chooser of the One: While the primary way for one to become a Hero is for the Chief God to choose a person for the job prior to birth and have them awaken to that power in their teens at the earliest, Saints also have the power to grant Hero status onto those who they deem worthy through a Hieromancy spell aptly named Heroic Blessing.
  • Cthulhumanoid: The Mind Flayer.
  • Clingy Jealous Girl: The Lamia and Medusa entries are noted to be quite possessive. The Lamia, in fact, hunts her husband (who may have been forced into marrying her) to the ends of the earth looking to strangle him to death if he cheats on her.
    • Charybdises don't take kindly to Scyllas scooping up men they've dragged, or are dragging, down beneath the waves, but are usually too timid to actually confront Scyllas about it.
    • The Shirohebi as well, though she has a non-violent solution to it. If she suspects her husband may be cheating on her, she'll use her magic to make sure his urges can only be satisfied by her.
  • Clone Degeneration: The Loli-Centric Sabbath created a special medicine to let Monster Girls live out gang-rape fantasies, the so-called "Doppleganger Medicine" (No relation to the MG of the same name). When given to their boyfriend, it splits said man up into numerous, sense-sharing clones based on how much is taken. However, the more clones there are, the more they all devolve into sex-crazed, bestial rapists for their girls' pleasure until the effects wear off.
  • Continuity Snarl: A lot, actually. A combination of different translators that don't always keep the correct meaning, outdated content, exaggerations, in-universe propaganda, a plethora of Unreliable Narrators and statements of the author that don't always correspond with what's written in official materials at least in part because not all of the books were even written by Kenkou Cross make it difficult to determine exactly how to view the setting.
  • Corrupt The Cutie: Absolutely EVERYWHERE.
    • Chaste Hero: No matter how negative or apathetic your view on sex is, getting demonic energy forced into your body will turn you into a sex maniac monster girl/incubus. Followers of the Fallen God especially enjoy corrupting the chaste and virtuous, including Angels, while Succubi find corrupting the normally stubborn, fastidious Elves to be most entertaining.
    • Alice succubi can't remember anything about sex, so they mentally remain like innocent children. Their bodies, however, gradually become more and more responsive after each sexual encounter. And their "husbands" are often those who have had their Big Brother Instinct slowly turn in a rather different direction because of the Alice's natural charm magic.
    • Elemental monster girls are curious about sex at first, but they're relatively tame compare to most monsters. However, as they continue to have sex with their contracted elementalists, the will slowly become corrupted by demonic energy, eventually turning them into sex maniacs. Furthermore, since they're elementals, their corruption will pollute the natural elements of the nearby physical world as well, transforming it into a fragment of the Demon Realm.
    • Background story of the fairy kingdom note how fairies were just innocent children who love fun games and sweet. It went off the rails when they befriend pixies and imps, as their magical energy got mixed and become succubi. Then pixies and Imps teach fairies about sex with humans, claim that it's just another fun and addictive game...And it's true, not to mention the spirit energy is the best sweet the fairies ever taste. Their mindset remain as innocent children, but the behavior change greatly.
  • The Corruption: Basically, demonic energy makes everything either monster girls, some kind of succubus, or physical embodiments of lust (elementals). Also makes everyone horny beyond measure.
  • Counting Sheep: The Weresheep has enchanted wool which makes those who come into contact with it drowsy, including the Weresheep themselves.
  • Covered In Gunge: The various slime monsters' preferred method of catching men.
  • Covert Pervert: The Sea Bishop, who doesn't even actively seek out a husband and only gets one when she has to transform him in order to save him from drowning, secretly takes notes from the couples she marries and, once she has transformed a drowning man, eagerly pounces him to try everything she's learned with him.
    • The Nightmare is a inversion of this. She appears as strong-willed and lustful woman in her victim's dreams to assault her target, but the real Nightmare is extremely timid centaur-subrace which will get paralyzed with fear simply by getting touched in the real world. But, as time passes, she'll become less and less covert.
  • Crap Saccharine World: The changes that the Demon Lord makes causes the land itself to become benevolent towards its inhabitants instead of apathetic and the Demon Energy means that everyone is hot. Though this may seem like a great universe to live in there are several elements of Fridge Horror to the series. Rape happens so often that it's not even considered particularly negative, some of the monster girls trap their husbands in And I Must Scream situations, Demon energy screws with people's heads, most of the gods are jerks or outright evil and if the current Demon Lord is killed, the universe will fall back into a vicious cycle that nobody benefits from. Kenkou Cross has recently tried to retcon or add world-building meant to soften this, particularly stressing that monstergirls do not spend all their time having sex 24/7 and their husbands can continue to pursue normal lives if they so wish.
  • Cuddle Bug: The Yeti love giving hugs to anybody. However, they especially like it if someone hugs them back.
  • Cute Bruiser: The Goblin is a loli who happens to be several times stronger than a fully grown man. Now in Oppai Loli variety with the Hobgoblin.
    • Also Baphomet, the most powerful demon beast, and the leader of the loli-cult called the Sabbath.
  • Cute Clumsy Girl, Dojikko: Hobgoblin. To quote her entry "However, perhaps because the enlarged portion of their bodies robs them of nutrients, they're often slower in the head than normal goblins. They're simpler than goblins, and perhaps because of the weight of their huge breasts, nowhere near as agile. When the goblins who formed a gang chase the man around, they're always the ones lagging behind. They're often observed falling down during the chase too.".
  • Cute Ghost Girl: Naturally.
  • Cute Monster Girl: Goes without saying. The entire purpose of the Encyclopedia is to catalog each and every one, and considering the number of monsters in popular culture, it isn't even half done yet.
  • Cute Witch: The Witch entry, natch. And all of them are loli.
  • Dark Skinned Blond: The Amazon, Dark Elf, Jinn of the Jar, Dryad, Girtabilu, and Ghoul all have dark skin and light colored hair.
  • Death by Sex: Amazingly enough, totally averted; none of the Horny Devils will explicitly kill you.
    • The Succubus Notebook reveals that the succubi of the former era often played this trope straight, milking captured men of essence until the men died. Over the years succubi developed as a culture and came to desire ways to make their meals last longer, be higher quality, etc. some even becoming able to genuinely love the men they fed on. Succubi learned how to make "prisons" to house captured men and provide for their needs, but milking them to death was still a ever present problem. Making going this far be physically impossible for monsters to do was one of the major changes the Overlord brought about when she came to power, so now monsters can feed to the limit on their husband via sex without worrying about overdoing it. Instead the man simply passes out once all the mana the monster can take is consumed.
    • In the former era, some races such as lamias and harpies still depended on human men to reproduce. However, no love was involved, and the men were typically killed once fertilization was guaranteed. That said, some members of these and other intelligent races were able to overcome the god-instilled instinct to kill humans, coming to love them instead and becoming sort of a married couple.
    • Avoiding this trope was one of the main motivations for the author to create the setting, as he loved the exotic and powerful monster women in various fantasy settings but didn't like how in most of them sexual relationships were either not possible or tended to end in depressing/deadly ways.
  • Deus Sex Machina: Originally, even the Demon Lord stood no chance against the Chief God. However, since the current Demon Lord is a succubus, she gained immense power by having sex with her husband, an ex-hero-turned-incubus. When the Chief God decided to deal with the Demon Lord by herself, the couple had more than enough power by that point to badly injure her.
  • Did You Just Punch Out Cthulhu?: Mentioned above, the Demon Lord and her husband beat the Chief God, successor of the creator of the setting's world.
  • Difficulty Spike: Mention in the background materials. Heroines starting their quests have a much easier time of it than heroes, since most monsters in the mortal realm have no interest in women. Things change for the worse in Demon Realm, where most monsters now have a distinctly Anything That Moves attitude and Tentacle Forests will violate any human girls that wander too close. The worst part is, since female humans draw spirit energy from their environment, they will slowly absorb the demonic energy of Demon Realm instead and will become succubi should they stay in the Demon Realm for too long. Heroes will have much less steep difficulty spike: every monster will be trying to get into their pants from the start, but they will gain spirit energy by eating and resting, and so far, there is no word that tentacles necessarily have any interest in males, so there may not be any new challenges in Demon Realm as long as they can repel monsters and have supply of clean food, save that they will encounter more monsters, and more powerful types thereof. That said, while it may take longer, men will also be transformed by staying in a Monster Realm, becoming incubi and having their values toward sex with monsters become very positive.
  • Distressed Damsel, Standard Hero Reward : Subverted. Often, when there is a maiden being held captive in a dungeon, it's very likely to be Echidna in disguise, waiting for a strong man worthy to be her mate.
  • Double Standard Rape (Female on Male): If you can't embrace this trope, the whole encyclopedia will be High Octane Nightmare Fuel. Justified because men with Femdom Rape Fantasies are one of the main target audiences.
    • Well, aside from the few types that usually or never force themselves on men (Holstaur, Unicorn, Inari and such). The Overlord is also seeking to gain enough power to remove the instinct that causes so many monster girls to be so aggressive in ravishing men (this would of course not lead to an end of seducing men or being very forward of course).
    • Its also important to note that per Word of God the term "rape" is not used in a serious nuance, and is more meant to instill the idea of a very attractive and assertive woman pushing you down and having her way with you while you bask in the pleasure.
    • Averted in setting, the monsters will rape men as part of courtship but don't mind when men rape monsters, some of them even enticing men to rape them as a sexual strategy. A monster will only take offence to being raped if she is already married or the man doesn't try to court her after the act. In addition, humans in setting who know that monsters try to rape rather than kill are still horrified.
  • Dracolich: If a Dragon dies without taking a human mate, she will be resurrected as a "Dragon Zombie." They generally have the same disposition as humans turned into zombies, i.e. endlessly craving sex.
  • Dumb Muscle: The Wurm is said to have immense strength and durability, as well as unlimited stamina. They are even said to uproot entire forests just because they were in the way. However, they are as dumb as bricks.
  • Eldritch Abomination: A passing hint was given in background story about the sea, about Demons of Chaos, a group of demons with power beyond the gods that were sealed away at the bottom of the ocean. A dark place that isn't ruled by Poseidon and no normal monster dares go near. They too, might have been changed into women, but this remains unconfirmed.
  • Elemental Embodiment: The Gnome (Earth), Ignis (Fire), Sylph (Wind) and Undine (Water) monster-girls. Also overlaps with Horny Devils, as they're also partially embodiments of pure "demon magic"; if they have enough sex, they become "corrupted" and start broadcasting it, transforming all the men and women within miles of them into incubi and succubi.
    • The Lava Golem is a Lava Elemental, though it's not said if they also have the power to change their environment.
  • Elves Versus Dwarves: Even the ones that have been turned into succubi tend to snipe at each other and fight over men. For some reason, succubi elves and dwarves usually target same men. Fortunately, their "fighting" consist mostly of squeezing the man between themselves.
  • Embarrassing Tattoo: A subversion. Many Monster Girls have intricate, quite stylish tattoos across their bodies (often featuring the MGE's trademark heart-symbol). The MGE book revealed these to be "Pleasure Runes", a magic which ups the sensitivity of any Monster Girl to pleasure. The larger and more covering the tattoo, the more sensitive they become. Though this has the side-effect of making it... difficult to go out, when the slightest touch can bring you to your knees, quivering in pleasure. For this reason only monsters that have abandoned living regular lives like Dark Angels cover a large portion of their body in such tattoos.
    • One of the Sabbath's most impressive accomplishments was research which allowed them to engrave the tattoos on clothes, letting girls remove the sensitivity-increasing runes if they wished. It also let the Sabbath cover themselves in more than their small bodies would normally allow.
  • Empathic Shapeshifter: Doppelgangers. Affection-based. See A Form You Are Comfortable With
  • Enthralling Siren: A kind of Harpy with a beautiful singing voice. They wear clothing reminiscent of an Idol Singer and share similar traits with other harpies.
  • Erotic Eating: A subversion with the Ghoul. Her mouth has evolved to be so sensitive, that it's considered a sex organ all its own, so anytime she puts something in her mouth is either masturbation or sex.
  • Everything's Better with Cows: Holstaur. To quote her entry "She, even as a child, develops nutritious milk. This milk increases the amount of spirit a man has, and promotes great health. This is of great demand among monsters, in order to make their husbands stronger and healthier, and sells very quickly, even among humans. She produces enough milk, that two people can live off of it alone.".
  • Everything's Better with Monkeys: Averted with the Kakuen. They're intelligent, yet selfish, Jerkassess and very lustful.
  • Everything's Squishier with Cephalopods: The Scylla, Kraken and Mind Flayer.
  • Everything's Worse with Bears: Usually averted by the sleepy, dopey Grizzly monster, as long as she hasn't been noshing on Honeybee honey.
  • Expy:
  • Face Full of Alien Wing-Wong: Monsters like Ropers and Slime Carriers can reproduce conventionally, but can also increase their number by implanting eggs/slime into the wombs of human women.
  • The Fair Folk: Sort of. Fairies and Leanan Sidhe aren't malicious unless a Succubus is involved. Played straight with the Pixies, however, who are actually typed as "Demons" rather than "Fairies".
  • Fairy Sexy: All the varieties of fairy might count to one degree or another, though many are child-like. The Titania, however, certainly counts. Their beauty is even described as "breathtaking".
  • Fallen Angel: What happens when Angels get corrupted by succubi. At first, the corruption twists their minds into thinking that sex is a proper reward for good deeds done by mortals. For a time, they still believe that they're doing holy work, rewarding good-doers with pleasure using their body. Eventually however, they will realize their own desire and fully transform into dark angels.
    • Downplayed with the Houri and Cupid. As servants of Eros, they're already so much like monsters in mentality that corrupting them hardly makes any noticeable difference.
  • Fallen Hero: Demon Lord's army has whole units made up entirely of examples of this trope. Just like the Fallen Angel above, these people were heroes who failed their mission to slay the Demon Lord. Men have been charmed and women made into succubi, and they have now reformed their parties under the command of the Demon Lord. Although they're probably the most powerful fighting force in Demon Lord's army, the former heroes are usually too busy screwing their heroines and only see actual combat when it represents a serious threat to the Demon Realm. Finally, the Demon Lord's husband is a mighty hero who may have slain the previous Demon Lord. But considering his motive, it's arguable if he's really fallen, aside from in the eyes of the Order.
    • The primary subject matter of the latest book released by the artist of the series, titled: "Monster Girl World Guide: Fallen Maidens".
  • Fan Girl: The Shirohebi becomes this to the man she falls in love with. She'll follow him around showering him with love and affection until he caves and gets with her.
    • Also the Nureonago, but she's more devoted and docile than the Shirohebi.
  • Fantastic Arousal: Many monster-girls, naturally, have extremely bizarre turn-ons and ways of showing it.
    • A succubus' horns are erogenous zones, and they enjoy having their horns squeezed and caressed by their mate.
    • Likewise, the heart-shaped tip of a succubus' tail is sensitive to pleasure, and they will play with it as a form of masturbation. They also have a number of cultural habits associated with it. They will gently wrap their tail around a man they like, and if he touches her tail it will be interpreted as an invitation to have sex. If he touches the heart-shaped tip it will be interpreted as courtship behavior and a marriage proposal. On the other hand, a succubus would never intentionally let a man she is not interested in touch her tail.
    • Ryus have a single scale, located somewhere under their rear, that grows backward. If this scale is touched by a man it will cause such a rush of pleasure that it sends the ryu into a lustful frenzy, wrapping themselves around the man and ravishing him nonstop until they are satisfied.
    • A sustained look at the color red will overwhelm both holstaurs and minotaurs with lust, again directed toward their husband or a man they like assuming they have one.
    • Lamia family monsters shed the skin of their snake half on a regular basis, and this induces a state of extreme arousal where their entire snake portion becomes an erogenous zone and they eagerly take advantage of the enhanced pleasure they can experienced at this time from their husband.
    • In addition to treating it as an expression of love toward him, Girtablilu find the act of stinging their man to be very pleasurable.
    • Basilisks wear masks not just to keep from using the power of their eyes on people unintentionally, but also because directly catching sight of a man causes them uncontrollable arousal that leads to them ravishing him. Conversely, while wearing the mask they are very vulnerable to being incapacitated by arousing stimulation, simply sniffing a man up close or having him whisper in their ear being enough to make them turn bright red and collapse.
    • The Tsurara-Onna can be aroused by caressing or licking the ice that sprouts from parts of her body, like her hip and eye.
    • As an inversion, a mershark that gets too wild during sex can be calmed by having her head patted/caressed.
  • Fantasy Kitchen Sink: Dragons, Mummies, Slime, Oni, Harpies, and that's just to get you started. And I do mean ALL kinds of fantasy.
  • Fantasy Pantheon: So far, we have The Chief God (who seemed to based on the Abrahamic YHVH, although background settings revealed that it's really a title and the current Chief "God" is a recently appointed goddess), Poseidon (who governs the oceans), Ares (a war goddess), Bacchus (goddess of Alcohol), and Eros (love goddess) (all goddesses), Bastet a Cat Goddess, and the Fallen God (who resides in Pandemonium).
  • Fantastic Racism: The pure elves consider humans, dwarves and any monsters to be lowly creatures and loathe to make contact with them, so they rarely get far from their Hidden Elf Village. Dwarves feel insulted by this attitude and hate them back. Meanwhile "Execute on Sight" warrants are issued, and monsters are hunted wherever The Order has strong influence, with exceptions for the Elemental family (minus Dark Matters) since they're considered "High Elementals" and not monsters.
  • Fauns and Satyrs: The Satyros; they're followers of the God of Alcohol and love to drink and brew wine, play their flute, and have sex. Surprisingly given their origin in myth, their patron god encourages a lot of civic-minded behavior, and the satyros often work as missionaries for them.
  • Fiery Redhead: The Ignis is not only this, she's literally on fire.
  • Fisher Kingdom: The Demon Realm. It's full of demonic energy, so anyone inside will become more lustful over time. And women naturally draw in energy from their surroundings when they expend it doing anything from fighting or casting magic to just breathing (as opposed to men and monsters, who only recharge from their own souls by eating and resting). When her spirit energy is completely depleted and replaced by demonic energy, she becomes a Succubus. Of course, by that point, she'll probably already be caught and transformed by a Succubus, a Vampire, a Dark Slime, a Dark Matter, or turned into a Roper after wandering into the Forest of Tentacles, or any one of a hundred other things...
  • Flower in Her Hair: Trolls, due to the fact that flowers tend to grow on their bodies. Also the Fairies.
  • Fully-Clothed Nudity: Inverted. Many monsters are actually naked, using retractable fur or scales to preserve their modesty.
  • Gag Boobs:
    • The massively well-endowed Holstaur uses her breast size as a form of communication. If she presses her breasts against you, it means she likes you. If she presses them against you firmly it means she wants sex. Now. They can even change size. Likewise, if you rub her breasts while she does this, she'll see it as returning the affection and will be very happy.
      • The Holsty's breasts are so impressive that even the lolification magic of the Sabbath cannot shrink them. Any attempts at turning a Holstaur into a loli have resulted in oppai-lolis. This was performed by the Baphomet Leader herself, and she consider it a personal Epic Fail.
      • The Holstaur's sister species from the Mist Continent, the Hakutaku, also sports an impressive pair, since her breasts are meant to be as voluminous as her knowledge.
      • Despite how the Sabbath in general tends to view large breasts on childish bodies, the Sabbath Grimoire reveals there is an entire Sabbath chapter made up of oppai-lolis run by a Baphomet named Marune who sports her own pair. This isn't on purpose though. It's just what happens to girls raised on the produce from the village she grew up in. It still caused a bit of a stir with the other Baphomets of the Sabbath and they were reluctant to accept her branch as legitimate until they tried her food and decided that her Sabbath's contribution was potentially valuable enough for them to overlook it.
    • The Hobgoblins are inferior to normal Goblins in every way except strength. They're The Ditz and Dojikko, yet ordinary Goblins will follow them around because they think "bigger breasts are amazing."
  • Generic Sexyness: Monsters are described as being beautiful compared to human women but most female humans shown are drawn in the same sexualized art style as the monsters. One freckled woman is drawn as "plain" but is certainly not unattractive, but as she monsterizes she becomes bustier and drop-dead gorgeous.
  • Gender Bender: Fairly rare, but with some exceptions. For instance, it is normally not possible to change the sex of a person by raising them as an undead, but a female skeleton monster can be made from male human bones (and will have warped memories as a result), though whether or not this is really a sex change is debated in-universe (since skeletons can be argued to be golems that use human bones as building material).
    • The Alp is a Succubus that was once an Incubus. A Homosexual Incubus or one that desired to be a girl. Their desire to be with men (or to be a woman) was so great, they (sub)consciously destroy their own ability to produce essence and thus turn into a monster girl, afterward, they cannot physically be distinguished from a normal succubus aside from potentially in behavior, and any children they have will be regular succubi.
      • Can also happen with guys who are in the closet, whether they know it or not.
  • Genius Bruiser: Baphomets. They're leaders of the Sabbath cult (see Mad Scientist below), and are stated to be the most powerful demon beasts as well.
  • The Ghost: So far, we've yet to see any of the major characters from the background setting info actually depicted in art, like the Overlord and Poseidon, and personal accounts of them are scant. There have been some physical descriptions of some of them though (namely the features lilim share with their mother).
  • Ghostly Goals: Subverted. It's said that ghosts can go to heaven should their business on Earth be done. However, in this world, all ghosts share the same goal, to keep having sex with the guys they like.
  • Giant Spider: The Arachne, Jorou-gumo, Ant Arachne, Ushi-oni and the Atlach-Nacha.
    • The Arachne is your basic "woman's upper torso where the head should be on a Giant Spider", who is something of a bondage-dominatrix due to being aroused when men struggle.
    • The Jorou-gumo is a more Japanese-themed version of the first, who acts as a Yamato Nadeshiko by day but at night turns into an MGE version of a sadist (i.e. no actual pain) that ties down a man she wants and ravishes him until he loves submitting to her.
    • The Ant Arachne is a type of arachne that mimics giant ants in order to mooch off their colony's work, find a home, and snag a man for themselves from those attracted by the ants' pheromones.
    • The Ushi-oni, having the lower torso of a giant tarantula, is the only one to have inhuman hands, is a violently lustful wandering rapist-monster girl, has a Healing Factor, and is the only one of the "Arachne" family known so far to transform human women into more of her kind.
    • The Atlach-Nacha is based on the Eldritch Abomination of the same name, and actually looks more human on her own than the others. This is because aside from extra eyes and some spider legs on her back, the giant spider parts of her consist of her transformed husband, she standing in a pouch formed on top of his body.
  • Go-Karting with Bowser: Even The Order tolerate aquatic monster girls. Since they're the only things to guarantee safe sea voyages (Poseidon won't summon storms against a ship if there is a monster's husband among the passengers) and the aquatic monsters are good guides.
    • Apsara are protected from attack due to their association with the goddess Eros (their temptations seen as trials), as are the gandharva in some regions (where they are declared divine beasts rather than monsters).
    • Kobolds are also tolerated as they are seen as mostly harmless pets. Mostly. That is its illegal to mate with them, but that doesn't mean people don't do it anyway and that the kobolds encourage it.
  • Godiva Hair: The Alraune, Nereid and Kejourou. Though in the latter's case, it's Justified.
  • Golem: The ones appearing in the Encyclopedia are made as statues with the forms of attractive women, though more mundane golems are mentioned in their entry. Should a golem fall in love with a man, she will remove the control runes that dictate her behavior on her own, then rewrite them to ensure her lover becomes her new master.
  • Good Is Not Nice: Read the Jerkass Gods entry below. It's hard to admit, but while the system enforced by previous chief gods is really cruel, it did keep the world in balance state for a very long time.
  • Gorgeous Gorgon: The entire Encyclopedia probably qualifies, but the Lamia, Medusa and Echidna are the most literal examples.
  • Green Thumb: Trolls can cause plants to grow in even the most hostile of environments. They even have flowers growing on their body.
  • Grey and Gray Morality: The Demon Lord honestly believes her plan will allow humans and monsters to co-exist peacefully. The problem being of course, that this plan involves turning Humans and Monsters into a single race with human men as the males and monster girls as the females and she only really got the monsters' consent for this plan, not to mention the fact that it didn't entirely work since monster girls can currently only give birth to more monster girls though she is trying to fix that. Monster girls in general don't seem to believe in consent and it can be argued that the transformation into a monster girl involves More Than Mind Control at worst (although exactly how much a human woman's personality changes after monsterization is a matter of great debate in the fanbase). The Order isn't entirely clean either, since they're still fighting the same war from before the change, lying to their people that the monsters still kill and eat people. Not to mention that it's their fault they lost Polove due to refusing Saphirette's request for aid simply because it held no strategic value and had no resources they could use, and it's further implied that they share the blame for the fall of Lescatie in Fallen Maidens due to the local Order higher-ups' mistreatment of the Heroes there.
  • Happiness in Slavery: Both the Chochin-Obake and the Karakasa-Obake, due to being tsukumogami, desire to be "used" by men more than anything. Though how friendly they are depends on how they were treated when they were still lifeless.
  • Hard-Drinking Party Girl: Both the Red and Blue Oni's practically live exclusively off of sake, and love to hold drinking parties. Likewise the Satyros, being followers of the God of Alcohol, pretty much spend their entire time drinking wine, making music and having sex.
  • Harem: While they themselves are always faithful to their single husband, most monsters have no problem sharing a man if they love him equally. Some, like Werewolves and Goblins naturally do this while others, like Lamia, are very opposed to it.
  • Harem Seeker: The Bicorn, as opposed to the Unicorn, actively tries to form a harem of monstergirls to satisfy their husbands.
  • The Hedonist: Pretty much all mamono are by nature only interested in pleasure of any kind. Whether or not they have standards when it comes to that or not is pretty unclear.
  • Hell Hound: Yes, there is one. Said to be so ferocious not even gods can tame one, though like all monsters have a lot of affection towards their husband.
  • Hermaphrodite: The giant slug species used to be this. The roper may also be considered hermaphroditic, seeing as how they use their tentacles to reproduce.
  • Hidden Buxom: If you look closely at the newly done version of the Yuki-onna you can tell that she's just as stacked underneath that kimono as the rest of the monstergirls.
  • High School AU: There are five spin-off profiles, "Succubus Eroge Heroine", which depict archetype Eroge high school girls of modern world turned into succubi. Not only is there the basic Succubus (the race that is stated to now define all monsters), there's also multiple different variants.
  • Horny Devils: Succubi are the most prominent monster girl in the setting with the highest number of subspecies. This is unsurprising given that the Demon Lord herself is one. The power she used to turn monsters into monster girls mean all monsters have succubus traits whether they're regarded as a succubus subspecies in universe or not.
    • The Alice is a rare mutation of the Succubus that looks and thinks like a pure and innocent young girl, but she exudes a mind-warping aura that eventually causes any man too close to lose his mind and rape her -- and her instincts mean she can handle and enjoy the sex, plus the man then becomes her husband and protector. After the sex, she forgets all about it even as her body is restored to its virgin state (though she retains a fondness for the man, and eventually she travels to Wonderland and unlocks her memories).
    • The Amazoness is basically a Hot Amazon Succubus with an appearance that invokes Nubile Savage and that lives in a society that is one part Boobs Of Steel to one part Amazon Brigade. Most of them have asymmetrical looks (i.e. one wing and one horn) and favor physical abilities over magic.
    • Alps are succubi that transformed from men who either were homosexual and/or wanted to be women. Physically there is nothing inherently different about them from the normal succubus race, and their children are regular succubi. The only true difference is that most Alps who hold on to their former male identity will continue to maintain an androgynous appearance and continue to act like men even with their husbands aside from the sex, while Alps who fully embrace their new found femininity will become "even more feminine than normal succubi" though this is apparently not always true appearance wise.
    • Dark Priests are Succubi that attempt to convert men to worship of the "Fallen God" through preaching and sex, dressing up in sexy nun outfits to boot. They are characterized physically by fairly small, feathery wings, and horns that curve to resemble or accentuate the look of a nun's hood.
    • Demons, formerly the parent species from which succubi evolved, are now considered a succubus subspecies. They are characterized by blue skin, black sclera, and a more extreme ideology than the average succubus when it comes to monsterization.
    • Imps aren't Succubi, but adopted the same feeding habits when they became monster girls (all monsters can and love to feed on men's essence, but only some make it their main diet).
    • Kunoichi are succubi that arose when the women of the unique culture of hidden ninja villages in Zipangu were monsterized. These succubi lack wings but possess incredible physical abilities, as well as various magical ninja arts. They also retain many aspects of the ninja culture in their behavior and practices.
    • Nereids are sea succubi, and are the typical transformation of women who drown in the ocean (Poseidon's power transforming them so they do not die). In their normal state they have fins instead of feet at the end of their legs, but like most other succubi they can readily use magic to disguise themselves as humans (and in their case to move easily on land). They lack wings, and their tails end in a large split fin rather than a spade shape.
    • Night gaunts are Eldritch Abomination succubi, with the requisite alien mindset and behaviors. Their husbands can transform to replace and become their wings, tail, and latex-like body covering.
    • Lilim (who are the direct biological children of the Overlord) are basically super-succubi, on the same level of power (or higher) as the highest tier monsters, and with beauty that can enthrall a man even without the use of a charm spell. They inherit from their mother a connection with the mana of all monster girl races, and thus the ability to transform human women into all kinds of different monsters (there are some limitations, depending for instance on the potential of the woman and the power level of the particular lilim). They also share with their mother white hair, white wings, and red eyes.
    • The females of the various non-human races that aren't considered monsters by default can only become succubi when they come into contact with demonic energy under normal circumstances. The monsterized versions of these races are categorized as subspecies of succubi and include Elves, Dwarves, and the various subspecies of Fairy (Fairies, Titania and Leanan Sidhe). The Dwarves in particular are almost extinct as a non-monster race (mostly due to the stupidity of their own males), Dark Elves also used to be a non-monster race, but they were already so hedonistic and depraved prior to the current Demon Lord's rise that they were more than happy to completely convert themselves, so not a single male or non-monsterized Dark Elf remains. Fairies may soon join them since they seem to only see becoming a monster as finding new ways to have fun (and they were already a One-Gender Race to begin with). Elves are the only hold outs aside from humans due to their prudishness, with their isolationist tendencies being enforced by a desire to avoid joining the others and them quickly exiling anyone who does get infected with demonic energy to avoid it spreading. The only exception to this rule are Elementals, whose classification remains the same regardless of if they're corrupted or not, and the various subspecies of Angels who continue to be classified only as angels even if they fall far enough to become Dark Angels.
  • Hot Amazon: Surprisingly not the Amazoness unfortunately. However, the Jinko and Minotauress are both very muscular Amazonian Beauties.
  • Hot Blooded: The Salamander, somewhat literally as well as metaphorically, and the Ushi-Oni in a dark, twisted kind of way.
  • Hot Teacher: The Hakutaku, who specialize in teaching those who come to them anything about monster girls they want to know, especially how to win over a specific monster girl.
  • Hot Witch: Dark Mages, who are mostly decidedly not lolis like the Sabbath Witches although they apparently sometimes get mistaken for them. They even serve as the example image for that trope.
  • Human Mom, Nonhuman Dad: Inverted. All of the monster races depend on human males to reproduce. The background material proclaims that this inversion is the core of the current Demon Lord's plan for peace; though she doesn't yet have enough power to make monster-girl couplings produce anything other than more monstergirls, she intends to make it so that they give birth to human sons as well. In essence, humans and monsters will become different sexes of the same race.
  • I Am Legion: Slime Queens, a mutation prevents them from properly dividing like other slimes do to reproduce. Instead they produce subunits of themselves to perform tasks their main body can't (as it typically becomes comparatively large and slow), and will sometimes grow to resemble large villages or even kingdoms of slimes (even trading with other villages!). Such large masses inevitably already have a "king" living there, supplying them with energy to maintain such a huge form, but the kingdoms are not necessarily safe for single men to wander into, as regular slimes often live there as well and it can be hard to tell them apart from the divisions.
  • I Just Want to Have Friends: Wererabbits. They're described as "lonely", and if they make a friend, they will not ever want to be separated from them. It's even worse if the rumors that Wererabbits can die of loneliness are true.
  • I Love The Dead: Played with. Here,the dead love you.
  • Immortal Procreation Clause: Monsters in general have quite low fertility rates, and its implied the longer-lived a monster is, the longer it takes for her to get pregnant; some extreme/unlucky cases having the monster not get pregnant after decades or even centuries of having sex a double digit number of times a day. Such monsters will attempt to trek with their husbands to special trees in the center of tentacle forests, seeking out the substance these trees produce which can ensure a single pregnancy when the monster has sex with her husband after she ingests it. Most attempts to reach the trees fail, the defeated couples sent back to the edge of the forest after getting all their energy sucked out by the tentacle plants, but the potential reward encourages them to try again and again until they succeed.
  • Interspecies Romance: A rather explicit (and not necessarily consensual on the male side) version, but the basic principle behind the setting.
  • Instant Awesome, Just Add Ninja: Succubi Kunoichi, who have been compared to the Disgaea Ninja many, many times, and become Ninja Maids if they "Assassinate" a high-profile target.
  • It Amused Me: The Fairy Queen does nothing to stop the corruption in her kingdom, she thinks it's much more fun this way.
  • Jackass Genie: The Genie is an interesting variant. Instead of twisting your wishes so they go wrong in some way, she instead will demand more sex than necessary to grant a wish if she doesn't like it.
  • Jekyll and Hyde: The Jorou-gumo. During the day? The sweetest, nicest girl you could hope to meet. At night? A sadistic, raging, rape-happy nymphomaniac.
    • Technically the Holstaur as well. Ordinarily sweet, gentle and placid, they become savage, brutal and as lusty as their Minotaur cousins if they keep looking at the color red or go too long without sex.
    • Also the Weresheep. Normally, they're quite calm and friendly, but that's only because of the tranquilizing effect of their own magical furs. Once their fur is shaven off, they become very vicious. This is actually important for their emotional health, if they are prevented from either performing or experiencing frenzied sex after being sheared it can lead to depression and low quality wool.
    • Trolls as well. Normally they're friendly and harmless. But if they spend too much time in sunlight, the monster realm plants on their bodies cause them to become very horny and even stronger than normal.
  • Jerkass Gods: The Chief Deity may or may not really love humans, but her (the current chief god is female) hatred of monsters only serves to justify the extremism of the Overlord. She's apparently unwilling to accept the changes to the monsters done by the current Overlord, as the monsters were created with the purpose of having a tool to keep mankind's population below a certain level (the motivation for this is as yet unknown). On the other end of the spectrum, the Fallen God takes the new Overlord's philosophy Up To Eleven. She believes in pleasure above all other things, and converts both human women and angels into her followers, causing them to desire the ultimate "reward" of being locked in eternal coitus with their mate in Pandemonium.
    • The cyclopes were once deities, but some fellow deities cursed them into monsterdom simply because they had only one eye.
    • Translations of the official background material have also shown that Poseidon (who is a goddess in this setting) turned against the other gods and sided with the Overlord in part at least because the other gods were forcing her to make storms to reduce human populations and make them fear the sea.
    • In more detail, monsters were living creatures whom the Chief Deity created so that the population of humans could be easily controlled. The previous Overlords? They were control devices so that the gods could control the monsters. Whenever the population of humans got too high, the monsters would become incredibly vicious and begin killing large numbers of humans. Then when humans started to die out and the monsters became too numerous, the Chief Deity would grant a human incredible power, creating a “hero”, and send them to slay the Overlord. With the Overlord slain, the monsters would kill each other to decide the next Overlord, causing a rapid decrease in the monster population. This would go on until humans again became too prosperous, by which time a new Overlord would have ascended to take control of the Monsters. This process ran for an unknown number of cycles until a Succubus managed to become the current Overlord, and started messing with the system.
    • A god of unknown identity (perhaps a previous Chief Deity) created the apophis as perhaps the first Overlord, and set them against the ancient desert kingdoms (at the time a flourishing beacon of human progress whose rulers carried the power of an ancient sun god), destroying them utterly.
  • Kimono Fanservice: The Yuki-Onna and Inari look great in their kimonos, but the Jurougumo and Youko look drop-dead sexy.
    • The Shirohebi, Ryu and Kejourou look lovely in theirs too. The Nureonago as well, in a way.
  • Knight In Shining Armor/Black Knight: Dullahans wear black armor, but morally they split the difference. To date, they're the only monsters that have been stated to fight out of loyalty to the Demon Lord rather than a chance to grab a husband and quit, demonstrating a knightly alignment. Morally... well, let's not get into that.
  • Knight Templar: The Order. Due to believing the Chief Deity's teachings that the monsters are enemies of humankind, an unnatural part of the world, and that the monster's female forms are meant only to trick humans, they make it their business to kill monsters and launch invasions into the Monster Realms and allied areas. They make no effort to spare the human "husbands" in the process, even if they were unwilling, to prevent them from spreading The Corruption, and some sects actually perpetuate the myth that monsters eat the humans that they kidnap so that people won't sympathize with them. On the other hand, it's mentioned that the clergy itself and most followers act more like a Saintly Church, and a special note is made that they aren't the great evil that monsters and monster sympathizers sometimes think they are.
  • Kuudere: Mantis. She acts like The Stoic her entire life, until she gets her first man during their Mating Season. After her first time, she'll be as dedicated to loving her husband as she is to hunting for food, though her affection outside of sex remains subtle.
    • Sahuagin counts, too. She never shows any emotion and rarely speaks, but is loving and vocal during intercourse.
    • Kunoichi are as well, as a part of their Ninja-Education.
  • Little Miss Badass: Half of the Sabbath cult (the other half are their Lolicon husbands). To start, their leader is the Baphomet demon general, all girls - both monsters and humans - are converted into lolis upon joining the cult, with humans being given magic power and becoming witches. The settings information even notes that the cult is actually the magic caster unit of the Demon Lord's army.
  • Living Aphrodisiac: All monsters are this to some degree. In fact, of the monsters that don't attack men by themselves, you can be sure they'll manage to make you so horny you'll attack them. Species that otherwise can pass as human (like dhampirs and kitsune-tsuki) can even have their true nature recognized by their husbands simply due to how incredibly good sex with them feels. Be it the charm effects of their mana, their bodily scent, physical mannerisms or even the taste of their skin when licked or sucked on, a monster's body is built to arouse and both give and experience sexual pleasure.
  • Living Toy: The Living Doll.
  • Load-Bearing Boss: The Demon Lord is one in a metaphysical sense. Should some hero manage to kill her, the old world design of the Chief God will come back in full swing. Meaning that all monsters will revert back to their former monstrous state, and start killing humans again - most likely starting with their beloved husbands. At a lesser degree, Lilims could also harbor this trope. Should any of them have enough power, she could become The Demon Lord's successor and can maintain the state of the world even if the Demon Lord were slain.
  • Love Freak: Lilim, just like their mother, want nothing more than to have humanity and monster girls coexist in harmony with love... expressed through sex. On the personal level, each Lilim is looking for one true lover to be her husband, despite having power to dominate as many men as she wants.
  • Love Is in the Air: The Alraune and many other monsters use pheromones to attract men.
  • Love Redeems, Love Makes You Evil : Demon Lord's husband is either of these, depending on who you're asking. He was made the most powerful human by the Chief God and tasked with killing the new Demon Lord, who had defied the Chief God by turning the monsters into monster girls and removing their desire to kill and eat humans. However, he sympathized with the new Demon Lord and they joined forces to make the world as it is now. They even fought the Chief God together when she (the current Chief God is female) appeared to slay them both for betraying her, won, and wounded the Chief so badly that she was forced to retreat and nurse her wounds.
  • Loveable Sex Maniac: The Merrows are the most lustful member of the Mermaid family and they never cease thinking about sex. However, when a Merrow proposes marriage to her husband-to-be, she gives him her hat. Said hat is the Merrow's Power Source and she can't even swim without it (unless she gets spirit energy from her husband). In other words, she puts her life in your hands when she asks for marriage. Furthermore, they are generally popular among other mamono, often trading away their lifespan-lengthening blood in exchange for dirty stories.
    • Another example is the March Hare. They are literally incapable of thinking about anything else than sex. No matter what men say to them, they will always interpret it as the man wanting to have sex with them.
  • Mad Hatter: There is a species of mamono based on this character. And while it's not clear if she is aware of her own insanity, she is intelligent enough to appear to be sane.
  • Mad Scientist:
    • The Sabbat didn't abandon their original purpose as the magic R&D unit. Some of their inventions include a technique to engrave Pleasure Runes on clothes and yet still remain effective, a medicine that temporarily turns a man into Naughty Tentacles and another medicine that will temporarily multiply a man into a group of sense-sharing clones (with decreased rationality according to how many clones are made).
    • The Sabbath Grimoire World Guide explains in detail the contributions that the Sabbath have made through their magical R&D experiments as well as introducing several different branches of the organization that specialize in different fields. Of these branches, Shirokuto's Sabbath is perhaps the one that fits this trope best as they're so strongly dedicated to magical research they don't indulge in the Sabbath's other activities of recruiting new members or advocating Lolicon. On the other end of the spectrum is Momonika's Sabbath, which is nicknamed the "Playground Sabbath" because Momonika and her followers spend all their time playing around and having sex with their Oniichans and zero time doing any magical research, though Momonika does design and sell clothes for monster children at least...
    • Liches are undead who ceaselessly seek knowledge, mostly sexual knowledge, and devote themselves to lewd and magical experimentation. They even remove their own soul and place it in a phylactery in order to be able to focus on recording their experiments rather than lose themselves to the pleasure they experience during such experiments.
    • Subverted with dark mages. Like liches, they do study to advance their magical skills, but they have no particular scientific goal in this, focused instead on enhancing their own pleasure and that of their husband.
  • Magical Girl: Turns out to be a class of heroine in this world, as Fallen Maidens features a magical girl named Mimiru Miltie. Possibly a Shout Out to a certain magical girl series, her fallen state being a Witch, one that is much darker in appearence than the one present in the Witch profile.
    • Almost ironically, Witches can become Magical Girls complete with transformation via Fusion Dance with a Familiar.
  • Magic Is a Monster Magnet: Magic is derived from Spirit Energy -- the more spirit energy you have, the more powerful a magic-user that you are. Monster-girls essentially feed on spirit energy, and so are drawn to powerful sources of it. The consequences of this is that magic-users find themselves very desirable to monster-girls.
  • Magic Contract Romance: Some monsters use this sort of scenario as a way to get a husband, including:
    • The four great monstrous elementals make covenants with human men they like, and given said magical covenant is sealed and recharged with sex the man also in effect becomes their husband. Non monstrous elementals also make covenants, in part due to their curiosity about and desire for human romance, the relationship inevitably becomes romantic if they are monsterized.
    • Demons make unbreakable magical contracts called "pacts" with humans as a cultural legacy of the former age where they used such contracts to destroy or ruin human lives. In the current age the contracts are in effect marriage compacts with mutual benefits.
    • It's possible for magic users to make sapient beings their familiar. To monsters, when this is done between sapient and sexually compatible beings, it's considered a marriage.
  • Magic Music: The Gandharva's music pacifies and arouses anyone who listens to it.
  • Mars Needs Women: Inverted. The monsters need human males to reproduce with to remain in existence. One end goal of uniting humans and monsters is to likewise make men dependent on monsters to remain in existence.
  • Mating Dance:
    • The Apsara's dance causes arousal into everybody who watches it. Either towards their own spouse or towards the Apsara herself.
    • Cancers (crab monster girls) have a courtship dance they do for men they like, an irresistible spectacle of rhythmic movements and bubbles full of mana swirling about them.
  • Meganekko: The Blue-Oni sports a very nice pair of glasses, and they're also calmer and nicer than their red counterparts... as long as she's sober.
  • Meido: The Kikimora are this. Dressed like maids, they very diligently do every household chore (and anything else) to make their husbands happy. They also encourage their master in all sorts of ways (including sexually of course) to become the best, most productive member of society that he can be. For this reason (as well as their past in the former era when they killed lazy men) some of them are actually attracted to lazy, unmotivated men, desiring to help them become better people.
  • Mermaid Problem: Averted, for obvious reasons. If you look hard, each mermaid-type monster has a indentation just below their waist, where the fish tail joins with girl body, and within this is a human-like vagina. Normally the actual vagina cannot be seen as the mermaid uses magic to conceal it with scales, but they can uncover it at will. The book's bonus art for the mermaid shows her genitals directly as well, while the bonus art for the merrow shows her engaging in A Date With Rosie Palms.
    • Among fans, the problem remained for quite a while with the Centaur and its subraces. No one knew for sure for some time which side of the body their genitals were on, they might even have had two, one on their horse side and another on their human side (as every centaur Kenkou illustrated had some kind of covering there). When the centaur's book profile was translated it was finally settled that they indeed do have two, the second having been developed when the centaurs became monster girls (Kenkou has stated it came about out of the centaur's desire to have the option to hold their lover close while having sex)
  • Miko: The profession of the Shirohebi lamia-type MG. They are shrine maidens in the service of "Ryus", water-aligned dragon monsters that are treated as gods.
    • Inari, who are also worshiped as gods, are often attended by human Miko, who can be voluntarily turned into Kitsune-tsuki in order to be closer to her.
  • Mind Rape: The aptly named Mindflayer consume human minds, though rather than destroying them it is more like they modify them to suit their preferences. Just what they actually do when feeding is rather mysterious, much as the mindflayers themselves are, but the pleasure of it is such that their targets inevitably come back for more and women eventually become mindflayers themselves.
  • Mix-and-Match Critters: A number of monster races can qualify as this, but the chimaera is perhaps the best example. Typically made up of aspects of goat, dragon, lion and serpent monsters (though there can be other mixes with more or fewer or different monsters), the chimaera is able to use the powers and abilities of every type of monster that makes up her body, albeit with the mitigation that each individual power is somewhat weaker than that used by the original monster race. She also will have a split personality consisting of the usual personalities of each of the monster types her body consist of, and each personality will demand attention and satisfaction from her husband. Her body can even change some aspects of itself depending on which personality is currently in control, becoming softer or firmer for instance.
  • Moe Anthropomorphism: Enforced in-universe, and somewhat weaponized, by the Overlord’s power. Originally, most monsters were the usual gruesome run-of-the mill man-eating monstrosities you find in most RPGs. Their transformation into pretty girls was a vital part of the Overlord’s plan to merge monsters and humans into a single species and enforce peace. It also granted these formerly animalistic races sapience and the capacity for human emotion.
  • Mon: The RPG is based on this concept. In other words, it's a harem-building game.
  • Monster Lord: The Demon Lord.
  • Moral Myopia: Both the Overlord and the Order are convinced of their own righteousness and that the other side is a force of evil (though the monsters are quite willing to recruit, forgive and marry all but the worst people even in the Order).
    • The Overlord's side is that the Order are a bunch of self-righteous puritans ruining her efforts to bring an end to a pointless war that the Gods created and forced upon both sides, as well as interfering with her efforts to gather enough power to improve the faults in her program, spreading blatant lies about her cause and murdering innocents who just happen to have found genuine love or simply sympathize with her cause.
    • The Order's side is that the Demon Lord has functionally destroyed two humanoid races, one of which (dwarves) was already on friendly terms with humanity (dwarves have been almost entirely transformed into toddler-like girls, non-monster girl elves are in decline), is determined to rip human culture as it has always been apart, is threatening humanity with extinction due to the "monster girls only birth monster girls" fact, is cheapening love with her minions' abundance of mind-ensnaring magic and powerful natural aphrodisiacs, and her efforts to subject people to More Than Mind Control are basically an attack on free will itself even when they don't involve turning someone into a parody of their former self.
      • To some extent or other, both sides are right.
      • It should be noted the argument regarding dwarves doesn't hold water, as Kenkou has confirmed that once monsters can birth males, male dwarves will be born to monsterized dwarves (as dwarves are considered a type of human). The same applies to elves. Of course, it may be the Order does not know this.
      • There's no real indication that the Order cares whether the monster girls ways of snaring husbands is cheapening love or not. The only thing that's really been said regarding their views of monsters is that the Order is essentially still fighting the same war they were fighting before the new Demon Lord took over and continue to tell people that monster girls still eat humans despite this no longer being the case. This a big part of why the Wandering Scholar started the Encyclopedia and why he was declared a heretic after publishing the first volume.
  • More Than Mind Control: Monsterization tends to fall under this trope to some degree. Monsterized women lose any previous inhibitions regarding sex they may have had and are filled with such a sense of liberation that they usually will quickly decide that they like being a monster and don't want to change back and will often feel gratitude towards the monster who changed them for "opening their eyes". How extreme a personality shift this causes depends on how repressed they were before their transformation, which accounts for the complete 180's the girls of Fallen Maidens underwent. Especially Wilmarina. Saphirette Spherica, meanwhile, barely changed at all personality wise. This is also why monsterized women are far more likely to monsterize others than those who were born monsters, since they know the "joy" of becoming a monster and want to share it.
  • Mother of a Thousand Young: Echidna are a mild case of this trope. Her first-born is always another Echidna, but every child afterward is random, it could even be a whole new species. But like other monsters, especially powerful ones, it's not exactly easy for them to get pregnant.
  • Ms. Fanservice: All monsters are this to some extent or another, or in one way or another. Many prefer revealing clothes or going naked, will actively or involuntarily try to seduce and/or rape human men, and some of them are fine with women as well.
    • Shameless Fanservice Girl: Monsters don't have many nudity taboos on what is considered tasteful clothing, some are aware of human taboos regarding this but aren't likely to care. Surprisingly enough most succubi draw the line on clothing that directly shows their vagina or nipples (at least in public), having their own particular sensibilities in what makes the most effective alluring clothing.
    • Innocent Fanservice Girl: Some childlike monsters like the Alice, emitting charm spells on people around them without being aware of it.
    • Even the human woman shown are able to compete with monsters in this trope.
  • Mummy: Was there any doubt?
  • My Girl Is Not a Slut: Monster girls come in 4 types based on number of sexual partners: Type 1, those who surrender their virginity to their One True Pairing and remain monogamously faithful for the rest of their life; Type 2, those who have nothing but casual sex until they find their OTP and then they become just like Type 1; Type 3, those who have permanent harems of husbands, comprised of all the men they ever have sex with and they always keep on adding to it; and Type 4, those who keep wandering and have sex whenever they encounter a man. For Type 3, there are currently only Charbidis and Slime Queen, while Type 4 are mostly savage beasts with little intelligence such as Devil Bugs. Normally, Monster Girls almost NEVER engage in adultery, though some form a harem to single husband if they all love him.
    • That was in the very first edition. As of the second edition onward, there are only Type 1 and Type 2, Type 3 has been modified such that those who prefer to be gangbanged will simply clone their husband into multiple bodies using magic instead of getting more than one husband, and Type 4 has been eliminated altogether so that ALL Monster Girls, no matter how apparently bestial or savage, will be capable of actually falling --- and staying --- in love with a man, who they will choose to be their one and only husband for the rest of their ageless existence. Word of God has expressly declared that the possibility of any adultery by a monstergirl with any male other than their spouse is absolutely zero, and any seemingly extra-marital sexual intercourse by the monstergirl with another female (who can only ever be a single bachelorette herself) never really counts as it is always just merely the means to the end of acquiring another sister-wife to add to the harem for the mutual satisfaction of both the monstergirl and her husband.
  • Naughty Nuns: The Dark Priestess is a Horny Devil whose whole shtick is that she preaches a "religion" proclaiming the holiness of regular sex and runs around in a fetishistic nun outfit. The Angel and Dark Angel kind of fit as well, given they are celestial beings who, particularly in the latter case, now live to have sex. There's also the Sea Bishop, a Mermaid-variant who has the fetishistic clerical uniform, but who is a loving, gentle and shy woman who performs the marriage ceremonies between humans and sea-dwelling monster-girls... which happen to involve the newlyweds having sex right there and then in front of the Sea Bishop (the act is combined with the sea bishop's magic to enable the man to live underwater), who secretly takes notes for when she finds herself a boyfriend...
    • The Roper specimen shown in the profile wears "ordinary" nun's clothing.
  • Naughty Tentacles:
    • The Scylla, being an octopus-based monster girl, has these-though they more often use their tentacles for binding and stimulating their mates than for actual penetrative sex.
    • The Roper is (are?) this combined with The Virus. They bind and rape human men, use their semen to create seeds, and plant those seeds on a human female, causing her to transform into another roper.
    • The Sabbat invented a "Tentacle Potion" which temporarily transforms men into near-mindless masses of tentacles. Often, they'll take these tentacles and use them as clothing until the effects wear off. The tentacle potion is also used to help a monster girl become pregnant faster or more easily as the tentacles produce a lot more sperm than the man normally can. Presumably this is useful because the monster girls bodies consume sperm and semen and thus getting enough inside them to actually have any left over to become pregnant is one part of what makes getting pregnant difficult for them.
    • Dark Matter does this as well, similar to the Roper.
    • The Monster Realm has locations known as the Forests of Tentacles. They are, predictably enough, a forest made out of Naughty Tentacles. Succubi and other monsters often bring their husbands to the outskirts to use them as marital aids, though they are wary of going deep into the forest where the trees are more aggressive. A human woman who wanders inside will be raped until she's either turned into a Roper by the forest or a Succubus by the Monster Realm's natural energy, and she'll probably want to come back routinely even after she's released.
    • And now there's a monster simply called "Tentacle" who came about from an intelligent type of tentacle plant called a tentacle brain. These plants desired to become monster girls, and the desire became enough to transform them.
    • Some monsters can give humans this. The mates of Mindflayers, Night Gaunts and Atlach-Nachas gain the ability to transform into a squid, demon-like creature and a giant spider respectively. The squid needs little explanation while the demon-like creature has many wriggling tentacles and the giant spider has a 'reproductive pouch' above their head that is a mass of wriggling tentacles.
  • Netorare: Averted with extreme prejudice. Once a monster girl finds a husband, absolutely nothing can ever make her have sex with any other man. Not Mind Control, Brainwashing, or even Laser-Guided Amnesia. Nothing. She might not even be willing to acknowledge that other men exist aside from her husband. On the flip side, a monster girl can always tell when a man is already taken, even by a human woman and would never steal that woman's husband or boyfriend from her. Though there's always monsterizing the human woman so she'd be more willing to share her SO with them.
  • Nightmare Fuel: Invoked; the Nightmare monster can invade people's dreams this way.
  • Ninja Maid: The Kunoichi are this to their husbands.
  • No Conservation of Energy: Most of the setting follows some fantastical version of the real world laws of conservation of energy and such, however, monster mana is the big exception. Through unknown means, when the Overlord gained her position and turned the monsters to monster girls, monster mana was also altered. Among the properties it gained was a miraculous ability to increase when interacting with/absorbing other types of mana, with the provision that for max effect the interaction must be full of affection (without this the increase is negligible). The result being that when a monster devours the essence of a man during sex, the mana she gains can be as much as double what she took from the man. In this way monsters can eat their fill while also being able to return energy to the man and thus keep him from dying from mana loss. This effect has also enabled monster societies to attain great prosperity thanks to the ease at which they can create excess energy to use as fuel for various magical devices or to maintain powerful and complex spells.
  • Non-Mammal Mammaries: Justified. Even if a monster doesn't nurse their young, being well-endowed is helpful in attracting mates.
  • Not Hyperbole: Inverted, the author himself has said that, as opposed to what is written in some pages, monster girls do not desire sex 24/7 and do plenty of other things in their free time. They do, however, see sex as at minimum having an equal priority to eating.
  • Obake: Many entries, including Oni, Kappa, two kinds of fox-girls, Jorougumo and Yuki-onna. They are pretty much exclusive to a section of the world known as Zipangu.
  • One-Gender Race: Every single monster race of the current era is all-female, although repeated sex with succubi family monsters (which includes vampires and dark angels) can turn a man into an incubus (which while filling the role of males for monsters are considered to be a enhanced human man with a monster girl's lifespan and capacity for sex), sometimes even in just one session. In reality, all the monsters transform men into incubi, but it takes much longer for most non-succubus races.
    • They weren't always one gender either (with the exception of races like succubi, harpies, lamia and such), but the current Overlord has put the world in its current state as part of her master plan. By her setting's definition, all monsters are female and all humans are male.
    • There are in the current age also various monstrous animals that in a sense avert this as they consist of both genders. Found mainly in Umbral Monster Realms, they are typically giant and monstrous versions of regular animals and often considered as monsters themselves by unlearned humans in the setting. However, because they do not produce monster mana (though they are affected by it) they are not considered monsters.
  • One-Winged Angel: Dragons and their subspecies are so powerful that they can transform into their old monstrous form at will. Though some of them dislike doing it for various reasons (not wanting to scare people, or the form not allowing for sex with humans).
  • Oral Fixation Fixation: Ghouls. Full stop.
  • Our Monsters Are Different: Well, they're all female. And horny - all the time, in fact.
    • Some of the beastman monsters have heat cycles and a few are better able to control themselves.
      • Well, there's enough monsters that want to rape men, to make sure men never leave the house. Unless you have a monster mate already, as it is stated most monsters will not attack a man who has been claimed by another monster (they can tell by sensing her energy and scent on the man).
    • All Trolls Are Different: They are gentle and intelligent in nature, look a lot like humans except for the tail, pointy ears and large hands and feet as well as flowers growing on their bodies. They have a strong affinity with nature and can cause plants to grow in even hostile environments.
    • Our Angels Are Different: If an already-corrupted Angel has too much sex, she can fall and become a Dark Angel. Also found in other flavors like the Valkyrie, the Houri and the Cupid.
    • Our Centaurs Are Different: There are normal centaurs, but then there are also the dream-invading Nightmares, the virgin-until-marriage Unicorns, the harem-seeking Bicorns, and the deer-derived White Horns. They're all incredibly lustful of course, though the vanilla-flavor ones at least try to restrain themselves unless something arouses them (though said something can, in extreme cases, be as little as a casual touch from a man), and the Unicorns thrive on Virgin Power, both theirs and their husbands'. Also, all centaur-type monsters have a second vagina in the front at the boundary of the human upper body and the horse lower body (according to Word of God, this is so they can remain face-to-face with their lovers while having sex).
    • Our Dwarves Are Actually Kinda Different For A Change: Dwarf females are toddler-sized little girls who're so good with their hands, the simplest touch makes men fall for them. The men are the same good ol' short, bearded, heavy drinking, jolly guys common in most RPG settings, though they're extremely rare now. When female dwarves began turning into succubi, most of them were very pleased about their brides becoming the kind of lustful woman they preferred to have while drinking after a day of work. Those who had wives that still hadn't become succubi actually wanted them to change, and sought to change their wives. Because of this the corruption spread like wildfire through the dwarven population. The male dwarves, and pure dwarves overall, are now on the precipice of extinction, with all new dwarves born female, beardless succubi. That said, male dwarves will be born to female dwarves as dwarven incubi once monsters become able to birth males (because in this setting male dwarves count as a type of human).
    • Our Demons Are Different: They all want to bed you (if you're male) or convert you (if you're female). If you're lucky, some may ignore you if you leave them be. Also, succubi make up the majority of the demon population now, so don't expect something like Diablo to pop up any time soon.
      • In-universe, "Demon" refers to a succubus subspecies with blue skin and black sclera who snare husbands by making men sign a contract.
    • Our Dragons Are Different: Extremely intelligent creatures, but are slaves to their instincts, which have been warped. Their snobbish aloofness is an attempt to hide their instinctual attraction towards human men (as they recognize human men are now the equivalent of males of their own species). They are now largely incapable of harming humans (save for in self-defense) thanks to the influence of the Overlord. Like any other dragons, they love to collect troves of treasure, and once they find a man who they eventually grow to love, they treat him as the prize piece of their treasure haul. If at some point this man proves himself stronger than her (a rare event as dragons value fighting ability and few humans can rival them), she'll become an incredibly subservient "Lizard Woman," though only to her husband. Also, they're the only monster girl known to be able to resume their original, true monstrous forms, though only for a temporary period of time.
      • They also have various subraces: the Ryu, Wyvern, Wurm, Jabberwock and Otohime. While they keep the Dragon's power to transform into their primal states, their appearance, abilities and behaviors are different in many ways.
    • Our Elves Are Better: And this (specifically their highly magical nature) is what grants the Succubus-infected ones the Heroic Willpower to (temporarily) keep from mating with "inferior" humans, as well as preventing them from gaining monstrous features like wings or horns. Even after becoming succubi they look down on and dislike other monster girls, paranoid that they will try to steal their men, and they still especially dislike dwarves. They also still prefer to live in natural surroundings rather than cities.
    • Our Fairies Are Different: They're tiny, playful, treat-loving and very energetic girls that are normally born from special flowers and weren't originally monsters, though monsterized Fairies do reproduce conventionally. Like elves, their highly magical nature (indeed, a large portion of their physical body is actually made out of mana) means their basic looks do not change with monsterization.
      • Also has two other subspecies: The Leanan Sidhe, who love and are fueled by great art, and the Titania, which are human-sized and the queens of the numerous Fairiy Kingdoms.
    • Our Genies Are Different: They're magic elementals that can grant wishes, but need to store up enough energy (read: have sex) first, depending on the scope of the wish.
    • Our Ghosts Are Different: Being spirits fused with monster mana, they are all lustful, no matter how they were in life. At first, they can't interact with the world physically and will possess humans. The victim will get his or her mind filled with obscene "Wild Ideas" (i.e. erotic fantasies) from the ghost, while the ghost will get essence by absorbing it from a male host until it's enough to manifest herself in physical world. By this time, a host will have been so filled up with 'Wild Ideas' from the ghost, that she will get to engage in sex directly immediately. In the case of a female host, she would likely be so overcome by the ghost's "Wild Ideas", that she'd become as much of a rapist as any monster girl, with the Ghost absorbing essence through the possessed woman's victims until she had enough to materialize and do the deed herself. Especially powerful/well-fed ghosts can become a higher-rank type of undead called a Phantom, and gain the power to extend their illusions/fantasies to their surroundings and thus play out complex and large-scale erotic scenarios.
    • Our Mermaids Are Different: Their blood can extend human lifespans, as in Japanese fables, though most apparently read lots of over-romantic stories about mermaids marrying human princes. There are various sub-races that vary a lot from the typical mermaids as well, including the devout sea bishops (who perform a vital role in sea monster culture via the marriage ceremonies they can perform to enable men to live underwater) and the fierce but well-meaning mersharks.
    • Our Orcs Are Different: They're chubby, pink-skinned women with pig ears on the top of the heads and literal pigtails (as in curly little stringy tails jutting from their rear), as well as being sadomasochists to whom, quite literally, Rape Is Love.
    • Our Vampires Are Different: Not as much as you'd think, strangely enough. The vampires of the MGE are of the classic, regal, powerful, blood-drinking variety (the classic cowl and cape they seem to wear actually being their shape-shifted wings). They do feel pleasure from feeding, as does their prey, but they consider going as far as having sex with a human to be beneath them. However, the men they capture to act as servants and food sources are actually also husband candidates. A man will become an incubus if they're fed from enough, at which point the Vampire warms up to the idea of making him her husband as she can now see him as no longer so beneath her. In some cases, she may even become like a doting housewife around him. While there is no mention of holy symbols, they are weak against sunlight and garlic. Being exposed to sunlight makes them become weaker than the average female human, while the simple smell of garlic makes them drunk - actually eating it will make them go wild like other succubi. If they have sex with a man before he becomes an incubus, and get pregnant from it, the child born will be a dhampir, a type of monster that has some of the vampire's strengths but none of their weaknesses (aside from the craving for blood). Dhampirs also lack the vampire's innate pride and are honest with their feelings. They tend to oppose and "defeat" vampires who do not admit to how much they love their husbands, using their vampire-subduing powers to get the vampire to be more honest (and sometimes making themselves second wives to the vampire's husband).
    • Our Werewolves Are Different: They run around in packs and gang-rape any man they find. Unless you defeat the one trying to screw you, one way or another, at which point she'll become loyal to you.
    • Our Zombies Are Different: They feed on essence - by having sex with men - instead of brains, and are all female but too dumb to distinguish between genders. Some may spend whole nights violating girls in futile attempts to get enough essence. Those that are well-fed, however, will over time regain their former intelligence and become more beautiful than they were in life. They even become able to reproduce, giving birth to the same type of undead as themselves (fueling in-universe speculation that undead are another form of life rather than simply animated dead). Especially powerful/well fed zombies can even become a higher rank type of undead known as a Wight.
  • Overly Long Tongue: the Akaname. She uses it to lick dirt off of her husband.
  • Pandaing to the Audience: The Ren Xiongmao. Translated from Chinese, the name means Human Panda or Werepanda.
  • Parental Incest: Dark Elves do not hate humans, but do treat them as sex slaves to be dominated. They then teach their methods to their daughters by practicing the methods on their mother's slave... who is of course their father, and in some cases they will fall in love with their father and make him her husband instead of journeying to find a man. The Devil Bugs, being Roachgirls, will also indiscriminately have sex with any male, including their fathers (and since they are such homebodies, this is usually what happens). As a culture, no monsters are truly opposed to incest (for them, being with the man you love is more important than blood ties), though for most races it is still a pretty rare occurrence.
  • Person of Mass Destruction:
    • The Wurm, due to her near-unlimited strength and stamina, can easily mow down an entire forest by herself when chasing a man.
    • Krakens are capable of sinking ships just to get at one man, and being rather lackadaisical and eccentric they see nothing wrong with such actions so long as they make sure nobody gets killed. This typically results in a sexual feeding frenzy as monsters rush to claim the rest of the men.
    • Almost any high-tier monster can be this if they want to be, notably powerful ones being easily capable of, for example, destroying a village on their own. Of course, nowadays they do not use such power to kill unless they have to.
  • Pettanko: The Harpy family (with the Gandharva being the exception) are all very flat-chested, presumably because they're bird-girls and so need to be aerodynamic. The Cockatrice is a flightless subrace of the same family, but is a swift runner, so the same principal applies. The Werebat, Honeybee and Beelzebub, three non-Harpy fliers, are also fairly flat, while some water mamono, such as the Sahuagin, follow suit.
    • Goblin definitely counts if they aren't lolicon.
  • Petting Zoo People: As noted elsewhere, a fair number of the monsters are this.
  • Pity the Kidnapper:
    • Whoever looks into the jar that a Jinn of the Jar's hiding in will get sucked inside and affected by charm magic. Since the very timid Jinn has no control over this ability, sometimes she will get raped by the man she pulled in.
    • Some monsters let themselves get caught by people who want to sell monsters as slaves, only to use their charms to make sure the man who buys them is one they want and that he ends up taking care of them as much as the other way around. The slaver himself will end up seduced by one of his "slaves" as well.
  • Plant Person: Alraune, Liliraune, Dryad, Kesaran Pasaran, Tentacle, Matango, Barometz and Mandragora.
  • Playing With Fire: The vanilla Dragon can breathe very destructive fire as Breath Weapon, while the Ignis is a Fire Elemental that can freely create and control flames. Salamanders possess flames on their tails produced by magical energy. These flames can be used as weapons or simply be harmless indicators of her arousal (both sexual and otherwise). The chimaera (assuming she is a typical individual and thus part dragon) can spew fire from both her arms, snake-headed tail and her actual mouth (though the flames are not as powerful as a real dragon's).
    • An interesting subversion with the Shirohebi. If her partner cheats on her (or secretly meets with other women), she'll actually solidify her raging jealousy into the form of burning blue flames of magical energy, which she then forces into the body of her lover. Following this the man burns with sexual desire, unable to be satisfied by any other woman but her. The flames inside him never completely leave, so he has to keep returning to her. She becomes "the water he must soak in."
  • Plot With Porn: Though nothing beyond a couple of Light Novels has been produced yet, the large amount of background info given with each Compilation Book released hints at a much deeper story than just sex.
  • Pop Quiz: The Sphinx casts a curse on a man that comes across her, then asks him a question. If he answers her question wrong, the curse activates, making the man so horny he'll offer himself up to the sphinx. On the other hand if he answers correctly, the curse will be reflected back on the Sphinx... making her immediately rape him.
  • Prehensile Hair: The Kejourou; in fact, their hair is an important part in sex for them.
  • Proud Warrior Race Gal: Quite a few, most of them Amazon Brigades, including normal Centaurs, Lizardmen, Jinko, Salamanders, Hinezumi and, naturally, Amazons.
  • Pure Is Not Good: The Alice is the most innocent and naive of all the monster girls; she doesn't even understand what sex is (though if she has enough she does change to gain a partial understanding). She also broadcasts an aura that will eventually Mind Rape a man into a loli-lover, who will proceed to first rape the Alice and then become her Stalker With A Crush.
  • Questionable Consent: A big aspect of the setting:
    • The Yuki-Onna will use a blizzard to draw someone to their home. After treating him like a guest she'll proposition the man and if he refuses she'll cast a spell to chill his heart so that he longs for the warmth of human contact. If he still manages to resist and tries to leave she'll create a blizzard to try to force him back.
    • Gyoubu Tanuki will use Sexual Extortion to try to seduce someone.
    • Subtext suggests that undersea monsters have the ability to keep their mates alive while underwater for a certain amount of time. However, that also suggests that men caught by them could either submit to them or try to escape and risk drowning.
  • Rape Is Love: Several monsters, through creative use of pheromones or magic.
    • Orcs in Dere mode. In fact, they have an outright rape fetish, and are fine being the rapist (in Tsun mode) or rapee (in Dere mode).
    • Since all Monsters think Sex Equals Love no matter what, none of them would ever mind being raped by their current or future husband. But they don't seem to understand that humans don't have that same sentiment.
  • Reality Warper:
    • Both the Overlord and Chief God can alter the setting of the world, although the Chief God simply struggle to keep the old setting rather than change anything.
    • Ares, the God of Fighting, is officially neutral, but in practice quite sympathetic to monsters and thus, it seems, bends reality to make it difficult for deaths to occur when monster and human armies fight each other. This, combined with the monsters' many ways to avoid killing means that deaths in human/monster conflicts are rare.
    • Wonderland is full of spells engraved into the very realm that enable the residents to cause all sorts of effects to occur by taking various, usually lewd, actions.
  • Red Oni, Blue Oni: One of the entries is a Red Oni, who is described as a super-strong party girl who likes to kick back, drink booze and have sex all day. The Blue-Oni is far more intellectual and composed than her Red Cousin...until she sees a guy she likes, then she drinks until she loses all her inhibitions, at which point she's just as bad, if not worse than the Red one.
  • The Red Sonja: The entire Lizard(wo)man race, along with their Salamander cousins.
  • Religion of Evil: The Religion of the Fallen God, supported by Dark Angels, Dark Priests and Dark Valkyries. Not necessarily evil per se, but unlike most other Monster Girls that have a bit of restraint, the Fallen Lord's worshipers practice sex 100% of the time, especially in Pandemonium, the Fallen Lord's realm where Dark Angels and Priests bring their husbands. Time is frozen there, and there is nothing to do but have sex.
  • Refuge in Audacity: Although the mere premise of the Encyclopedia may be this, being raped by a sentient mushroom certainly is.
  • Rescue Romance: The Sea Bishop commonly gets a husband by saving a man on the verge of drowning. They do this by having sex with the man to infuse their bodies with magical power so they can live underwater.
  • Sand Worm: Rather special among monsters, their external shell is in the form of the same gigantic, armored worm monster they were in the former era. Inside however, attached to the shell via a fleshy umbilical cord that they can freely change the point of contact with, is a pink-skinned woman who functions as their genitalia as well as their brain and the core of their being. They "eat" men by taking them into their shell to have sex with their womanly core. The room-sized spaces inside their shell thus become their husband's new home, complete with magical light for visibility, fleshy equivalents of furniture, and even dry cavities for storing their husband's belongings. Its important to note that they cannot detach themselves from their shell as it is part of their body, albeit powerful individuals (i.e. ones that have increased their mana stores through sex) can learn to shrink the shell down and reform it so that they end up looking a bit like lamia. They do this in order to travel/go on dates with their husband in towns where the normal size of their shell would prevent them access.
  • Scary Scorpions: The Girtablilu is part of the "Arachne" family, and thus appears as the upper body of a human woman replacing the head on a giant scorpion. A skilled hunter, she's a sadist who compulsively stings a man she takes as her "husband" as a sign of affection. By sheer coincidence, this stinging comes faster and more frequent as she feels more turned on/falls deeper in love, her venom is a combination of paralyzer and aphrodisiac (and greatly boosts semen production), and prolonged exposure to her venom eventually mutates her husband's nerves so that he actually derives as much pleasure from being stung as she derives from stinging him.
  • Serious Business: Surprisingly, despite the MGE being a sexual fantasy, a lot of people can debate quite intensely about the morality of the setting's Demon Lord and her plan.
  • Sex Equals Love: The entire essence of the Demon Lord's plan to bring world peace. Therefore it is part of the core instinct of all monsters.
  • Sexual Extortion: The Gyoubu Tanuki uses this to get a mate.
  • Sex Slave: The Orcs, Amazoness and Dark Elves are the most blatant but a lot of monster races are willing to rape and kidnap unwilling men, forcing them to provide both offspring and sexual pleasure. Some monsters also won't admit their love for a man, continuously referring to him by monikers like slave and stating that their copulation is only for her pleasure.
    • Happiness in Slavery: Men captured and taken as husbands tend to come to love the monster back due to both her sexual skills and acts of affection. The setting's information does clarify, that monsters that refer to their man as a slave or as prey are essentially synonimizing it with "husband" and a strong love can be seen in how they treat the man despite the terms they use.
  • Shout-Out: While a majority of the monster races are based on mythological creatures from ancient stories, a good number are instead inspired by characters or creatures from various famous RPG franchises.
    • The Gazer is clearly based on the Beholder of Dungeons and Dragons, to the extent that when he posted her profile KC actually joked about the name with a last second word swap to avoid copyright issues.
    • A number of the slime races are humanoid versions of various types from the Dragon Quest games. Aside from the basic blue Slime, notable examples include the Queen Slime (referencing the King Slime) and the Parasite Slime/Slime Carrier (referencing the Slime Knight).
    • The Mindflayers are as obvious as can be, the only distinction in the name compared to their Dungeons and Dragons origin being the lack of a space between the two words.
    • The kunoichi's design seems to have been heavily influenced by a ninja from Disgaea.
    • The designs for the Gyoubu Danuki and the Crow Tengu resemble Namizou and Aya respectively from Touhou.
  • Shy Blue-Haired Girl: Nightmares are extremely shy, and have light blue-purple hair.
  • Shrinking Violet: The Doppelganger's true form is that of a shy and timid little girl.
  • Sinister Scythe: Both the Baphomet and the Nightmare are seen with rather elaborate scythes, while the Mantis has a scythe-Like blade attached to each of her wrists.
  • Single-Target Sexuality: No matter how lustful or promiscuous Monsters may be, once a Monster has imprinted upon a man as her husband, he becomes in a sense "the only male in the world that exists", so they'll no longer be interested in sex with anybody else.
    • The Extremist Faction of monsters at first glance avert this, as even when married to men they continue to zealously monsterize women (and sexual relations are one way they can do this). However, for them its not about attraction or sexuality, but rather simply a means to make the Overlord's ideal world come about more quickly and to prevent human suffering.
  • Sirens Are Mermaids: Subversion. Mermaids do love to sing, and men who hear their songs will get charmed. However, there are also actual sirens, a bird-human hybrid just like in Classical Mythology, with similar magical songs. While mermaids just love singing, sirens sing with the intent to get husbands.
  • Sleepwalking: The Dormouse are capable of walking around while fully conscious during their sleep.
  • Sleepyhead: The Dormouse are almost always sleeping, and when they don't they are always drowsy. However, they are capable of walking around and talking to people while they are asleep.
  • Snake People: The "Lamia family" of mamono.
  • Snakes Are Sexy: The premise of the Lamia, Echidna, Medusa and Shirohebi races.
  • Snow Means Love: Played Straight. There's a Yuki-Onna Monster Girl, but luckily she prefers to take in and mate with men she leads astray in snowstorms.
  • Spider People: Arachnes
  • Stalker with a Crush: The Lizardman entry says if someone defeats her she'll offer herself to be his wife and if the person refuses she'll most likely stalk him until he changes his mind. Given her appearance, this isn't necessarily a truly terrible thing...
    • Likewise the Dullahan which will out and out hunt the man she likes down to bringing him back to the demon realm... and she always finds her quarry.
    • Young Kappas will play with male children around their age, not simply because they enjoy human company, but because they're picking out husbands for the future. Yuki-onna do the same thing when they are young.
    • The lizardman's cousin race, the Salamander, does this in a more blatant way. She'll stalk the man she likes but is not quiet about it, taking every opportunity to shout to the world about how much she loves him and wants to be with him, as they tend to act without thinking things through first.
    • In fact all monster girls can become this to an extreme extent. That is once they come to recognize a man as their husband they gain the ability to sense his particular spirit energy and track him down no matter how far he may try to flee from her.
  • Stripperific: It's stated that most monsters prefer these kinds of clothes due to it helping to attract mates. Even when their 'clothes' are actually retractable fur or scales it still show a lot of skin and doesn't hide their figure.
    • A lot of the human woman shown also dress like this, either wearing tight outfits or revealing ones. Maybe they're trying to compete for husbands with monsters?
  • Stop Being Stereotypical: Due to the monsters' predator instincts, most of them tend to be aggressive in acquiring a mate, even if they have to drag him away kicking and screaming. This, of course, makes it very easy for the Order to portray them as evil beasts that eat their human "victims".
  • Super Drowning Skills: An interesting subversion with the Nereid. They'll drag women down under the waves and drown them...only for the victim to be reborn as a new nereid.
  • Super Not-Drowning Skills: All the undersea monsters. Sea Bishop especially for being able to give husbands of such species the ability to breath underwater. The ritual, of course involves sex between the wedded couple.
  • Super Strength: Monster girls are stated to be physically stronger than average humans in general. Red and Blue Oni, Ogres, Goblins (Hobgoblins especially), Vampires and Minotaurs are all to varying degrees explicitly stronger than even most trained humans. The monsters with the greatest physical strength are, surprisingly enough, the loli monsters called baphomets, albeit dragons are not far behind them (noted to be able to make the ground shake with a simple stomp of a foot). Wurms are not as smart as vanilla dragons but just as strong, noted to be able to plow right through forests and huge boulders. Such monsters can only be challenged by the strongest of heroes.
  • Taken for Granite: Medusas use this technique to kidnap desirable men. The Cockatrice also has this power. Luckily, the effects are reversible. Also, Gargoyles turn to stone when the sun rises -- and if they're on top of a man when it happens, he does too.
  • Tanuki: The Gyoubu Danuki. Has large, bulbous pants, and is apparently a Proud Merchant Race. Described as a "Bad Girl".
  • Tenchi Solution: Monster Girls in the MGE are generally monogamous, but in some situations will form a harem for a single husband. He must be able to satisfy them all however. Thankfully a by product of an incubus having sex with multiple monsters is that it boosts his own ability to produce essence even further to compensate.
  • The Slacker: Due to the monsters' hedonistic nature, they tend to be stereotyped by humans as poor workers, however the truth is much more complicated. Many monsters that have jobs do indeed approach work in a rather carefree way, readily taking time off and having irregular hours. However this is not due to laziness so much as differing priorities. Monsters all have longer lifespans than average humans, and thus tend to live unhurried lives, having a different sense of time compared to a human. Further, provided they are married they have little real need for money (since if they need to they and their mate can survive just off each other's energy), and thus only desire to make enough money for them to buy things they like or want. However, if the payment for work is something they greatly value, for a instance a man, then most any monster can work with incredible zeal and capability. Some races on the other hand are very diligent and hard workers by nature, such as giant ants, dwarves, dullahan and cyclopii.
  • The Theme Park Version: In-universe example. The Order's lore claims that "The wicked Demon Lord who emerged from the darkness is working from the shadows to destroy humanity". Fact is, the Demon Lord and the monsters were included in the design of the "World" that the Chief God created. See Jerkass Gods entry above for detail.
  • Three-Way Sex: It's mostly 2 girls and a guy, though Sabbath's Doppelganger Medicine can create a girl and 2 guys scenario (although they would prefer many more guys in this case).
    • If it turns out that a Doppelganger's target's beloved woman did actually love him back, then when she sees the Doppelganger borrowing her form, they will be linked through demonic energy, causing the woman to slowly change and eventually become a monster like the Doppelganger. Then they will have sex with their beloved man together.
    • As lustful monsters, elves and dwarves often tend to take a liking to the same man, and it often leads to the usual Elves Versus Dwarves. Except that it won't develop into the kind of fight where they spill each other's blood. Instead, they both snuggle up against the same human man, pinching him between them.
    • In case of elementals, if the covenanter from when they were a pure elemental was a woman, the demonic elemental will also change her covenanter into a monster the same as herself. After the demonic elementals change them into succubi, succubi elementalists will use the elemental's power to assault human men, and they'll end up having threesomes all the time together with the elemental.
    • The Liliraune focuses exclusively on this. It's a variant of Alraune with two women inside the flower. If they find a husband, they sandwich him between them.
  • Too Dumb To Live: The Dwarves no longer exist as a full species because after liking the changes that happened to their women becoming Succubus they decided to do that to their whole species. Since Succubus can only give birth to females you can guess that it ended well.
  • Tomboy: Many Alps don't embrace all aspects of their change and will continue to act like men. Although they won't mind having sex with men, eventually.
    • Tomboy And Girly Girl: Those who welcome their change, however, become even more feminine than actual women and get the bodies to match. It's not always either/or though, with some that embrace femininity retaining a tomboy appearance, and others that retain tomboy behavior still gaining very feminine bodies.
  • Trope Overdosed: As if this page wasn't obvious enough. Each monster embodies at least one trope, and there are plenty of monster girls.
  • Tsundere: Dullahans. Tsun with their head on, Dere with it off.
    • Orcs are Tsun or Dere depending on whether they or their lovers are dominant.
    • Vampires are Tsun, at least until their lovers become an incubi, whereupon they, sometimes, become Dere.
    • Dragons are usually Tsundere, their tender feelings often hidden by their prideful attitudes but still showing through as they treat their husband as their great treasure. In the rare event a Dragon's husband proves to be more powerful than them they will go full Dere.
    • Manticores deeply love their husbands, like any monster, but rarely will speak their true feelings.
    • Background stories also mention that the Demon Lord is this. It hasn't made her marriage unhappy as she's had many daughters even with the Immortality Procreation Clause in effect.
  • Thou Shalt Not Kill: A mandate imposed upon the monster races via the Overlord's power, done in order to counter the human-killing mandate the gods instilled in monsters. Since the entire idea behind the monster girls is to achieve peaceful coexistence and oppose the old ways, all monsters find the idea of killing a human to be abhorrent. That said, they will still kill in self defense or the defense of their loved ones, some types doing this more readily than others, but even then using nonlethal means is preferred.
    • There are, however, plenty of monster girl species who have been stated to violently brutalize men they catch, some with weaponry, some with their own eldritch bodies. Luckily, it's stated that, physically at least, the men are not harmed to any appreciable degree by even the more extreme behaviors. Monster mana is stated to even automatically protect the man from the claws and horns of his mate during sex, it being basically a built in reflex to help monsters be with humans safely.
    • Even the notably jealous lamias will not truly harm their husband if he cheats on them, instead coiling tightly and ravishing him so thoroughly that their claim on his love is indisputable.
  • Twin Threesome Fantasy: Doppelgangers might make it happen. Also pretty much the fetish the Liliraune caters to.
  • The Undead: The Zombie, Ghoul, Skeleton, Ghost, Will-o-the-Wisp, Wight, Doppelganger, Vampire and Mummy entries. Dragon's update profile from compilation book also mention Dragon Zombie.
  • Unicorn: They're Centaurs who stay virgins until they marry and only seek virginal husbands too. Not that this makes them less dirty-minded.
  • Unreliable Narrator: Understanding the role this plays in the MGE profiles is essential for fans interpreting the works. The Wandering Scholar (the in-universe author of the profiles) is prone to hyperbole in his descriptions, and also often writes from the perspective of short-term observations and interviews. As such, when it comes to descriptions of daily monster life, Saphirette (another in-universe author) is considered more reliable.
  • Unwanted Harem: If a Goblin takes a liking to you, the Goblins will bring you back to their village. And you will have to do it with all of them.
    • This applies to a lot of pack-oriented monsters, actually. Like the Werewolves or Orcs.
    • That said, the sexual skills of monsters and the love they give mean the harem will likely not be unwanted for long.
  • Unusual Euphemism: The Kunoichi's "Assassinations" consist of them sneaking into the home of their target, and seducing him with utmost ease.
  • Uplifted Animal: Of the physical as well as mental variety (i.e. gaining a humanoid body and sapient mind). Done in two main ways:
    • 1. Before the current Overlord came to power the majority of monster species lacked the ability to speak, and most also lacked sapient intelligence as well as the capacity for much emotion. While technically not animals, there wasn't much to distinguish them from animals. The current Overlord's ascension and the beginning of the age of monster girls enabled her to change most all these races (with a few odd partial exceptions like the parasite slime) to grant them humanoid bodies and sapient intelligence. While the degree of intelligence still varies greatly, all monsters now have the ability to speak human languages as well as experience human levels of emotion.
    • 2. One consequence of the way monster mana works is that it is heavily influenced by emotion, especially feelings of love toward a human. As such, while normally an animal would never become a monster girl no matter how much monster mana they are exposed to, if that animal loved a human man enough then the mana could cause them to change into a humanoid form (gaining sapient intelligence and the ability to speak) and become monster girls in order to love the man sexually and live with him as a wife. Dogs and cats are the usual examples of this, giving rise to the cu sith and cait sith races. They are easily distinguished physically from normal dog and cat monster girls by how they tend to be covered more fully in fur, have longer snouts, etc. They essentially look similar to the usual version of a Furry.
  • Valkyrie: They are warrior-angels serving the Chief God. Just like regular Angels, they have a corrupted version named "Dark Valkyrie" who, despite being technically followers of the Fallen God, are only loyal to their husbands. Unlike regular angels though, valkyries can be corrupted into monsters and not go into a "dark" form, depending on the circumstances of their transformation they can remain as pure-looking valkyries, continuing their heroics but now following their and their chosen hero's own concepts of justice rather than obeying the gods alone.
  • Violently Protective Girlfriend: While it's said that Monsters hate killing or hurting anyone, they'll become very dangerous and ferocious if their loved ones are in danger. Especially noticeable with the ferocious Hellhound, whose fury if someone tries to harm their husband is described as "the sight of hell", it is also notable that is what will happen "even if the enemy isn't killed", implying surviving is the odd outcome rather than the norm and the "sight of hell" is the best case scenario. Black harpies are likewise noted to behave like the monsters of the former age (i.e. human killers) if their family is harmed.
    • To give an idea, a small side story about the early days of the Overlord's rule talks about how a Succubus (implied to be the Overlord) and her husband were attacked by dangerous tentacle plants (they were not monsters technically and thus at first maintained their human-killing behaviors). When the man was slightly injured by them (he repelled their attack but got scratched in the process) the Succubus vaporized all the nearby plants with a huge fire spell and afterwards called in a group of powerful monsters from the Overlord's army who proceeded to level 90% of the forest in half a day. This cowed the tentacle plants to such a degree that a vow to never again harm a human, especially a man, was etched into their very nature. Thankfully for the tentacle plants, they discovered they were able to feed on the monster mana produced by nearby monsters coupling with humans, thus giving them a way to survive peacefully, as well as a role in the new world as sexual helpers.
  • Virgin Power: The Unicorn toys with this. Her magical powers get weaker if she has sex, but only if her lover has had sex with monster-girls other than her.
    • There's also the even weirder/kinkier example of the Alice monster; her Virgin Power drives men to ravish her (and despite her innocence her succubus instincts means she can handle the sex just fine). And when they're done she gets Easy Amnesia and becomes a virgin again (until that is she has an inevitable adventure in Wonderland, the experiences there enabling her to regain her memories of sex, albeit she still retains her innocent, playful personality).
  • The Virus: Many monsters, most notably the Succubus, and always targeting females. Others include the Werewolf, Matango, Roper, and Dark Slime.
    • The Matango has a rare ability to change men; if enough of her spores get inhaled, he turns into a "mushroom person" similar in appearance to the matango but male.
    • If a woman puts on a Mad Hatter's hat, they will become one themselves.
    • And with the introduction of the Lilim, a woman can now be transformed into almost any monster (though some monsters need specific conditions to be met and not any woman can become just any monster). Men also become Incubi when coupled with monsters for long enough, and though they technically aren't monsters themselves, they behave the same and can act as The Virus to human women on behalf of whatever monster species changed them (though there has never been a case of an incubus raping a human woman, their desires being squarely centered on monster girls).
    • Definitely the aptly named Parasite Slime. They're a unique variant of Slime that, instead of taking on human form themselves, enter the body of a human woman, fuse with her, mutate her body internally and change her personality in some ways (though not her basic self). When the fusion is complete, they'll become known as a "Slime Carrier".
  • Voluntary Shapeshifting: Many monsters can disguise themselves as human women, and most all can take on a more humanoid form via the polymorph spell (though if they lack skill they may retain their original skin color and other features). The various Dragon monster girls are standouts, being the only monster girls known that can transform into their original monstrous forms. Nekomata can disguise themselves as ordinary cats. The Doppelgangers take on the form and personality of their husband's ideal woman.
    • On the men's side, Wendigos, Mindflayers, Atlach-Nachas and Night Gaunts give their mates the ability to turn into an ape-like creature, a squid, a giant spider and some kind of latex tentacle beast thing respectively. Those men can voluntarily change back but their wives prefer for them to be in their transformed form when in public. This is because they are comfortable with having sex in public when their men are in the transformed form but not when the men are in human form.
  • Weaksauce Weakness: Some mamono have this.
    • The Mimics and Jinns of the Jar become powerless if they are ejected from, respectively, their chests or jars. With the Mimic you just have to shove a key in the keyhole of the chest, and with the Jinn you just have to throw something in their jar or just break it. Such an action also breaks the jar/chest they wear on their body, but as it is a construct made of mana they can reform them once they have a chance to recover their powers.
    • The Werebat is terrified of lights, and will therefore become submissive if exposed to bright lights, but only for as long as she is exposed to them.
    • The Hinezumi becomes calm and timid if her flames are extinguished with water or a man's essence.
    • Giant Slugs become smaller and weaker if salt is poured on them.
    • If the dish on top of a Kappa's head dries up, they will lose their strength.
    • Vampires become nearly powerless when exposed to sunlight.
    • Oomukades are overcome by incapacitating levels of pleasure if they take the saliva of a man into their bodies, but even knowing this they often end up kissing their husband anyway out of love and passion.
  • Well-Intentioned Extremist: The current Demon Lord, a succubus, had decided to try to fix the ages-long mutually genocidal war between mankind and the monster races. Unfortunately, her method of doing so has caused the world to sink into its current state. While some welcome the change, those that don't aren't given a choice in the matter.
    • Differently so, the current chief celestial power recognizes that she (The Demon Lord) hasn't left the world in the best state. Unfortunately her method of dealing with the problem seems to involve forbidding humanity to make contact with monster kind, and resorting to genocide when necessary. The Chief God actually controlled the previous Demon Lord, using his control over the Monsters in order to prevent the overpopulation and self-destruction of humanity, and thus is the reason for man and monster's old eternal war.
    • Then there's Saphirette Spherica, the leader of the Elementist Association and in Universe Co-Author of Demon Realm Traveler's Guide. Formerly a human Elementist who studied elemental magic and natural history to save her dying home land of Polove, when her attempts to revitalize the barren soil of her homeland with the aid of the four elemental spirits she'd contracted with failed, she tried to ask the Order for help but her pleas fell on deaf ears (according to her because the Order saw no strategic value in Polove). This lead to her charging straight into a Demon Realm in a desperate bid to monsterize her elementals in the hope that this would make them strong enough to try again, which lead her to getting monsterized herself as a Dark Matter. This finally allowed her to succeed by transforming Polove into a Bright Green Demon Realm. Needless to say she is a big time pro-monster advocate as a result and Traveler's Guide is mostly her talking about how great the Demon Realms actually are (while also advertising for a husband, much to the Wandering Scholar's annoyance).
  • When Trees Attack: Dryads, Alraune and Liliraune are like this... just replace Attack with Rape.
  • White-Haired Pretty Girl: The Lilim, Dark Angel, Dark Priest, Dark Elf, Shirohebi, Ogre, Yuki-Onna, Yeti, Unicorn, Ghost, Zombie, Skeleton, Holstaur, Arachne, Cockatrice and Ren Xiongmao all have very light hair, varying from white to various color-shades of silver. And while we never see her, the Demon Lord is probably also an example, as Lilim apparently strongly resemble their mother.
  • White Magic: Actually invented by a monster, surprisingly. Specifically the Baphomet Grellia, the leader of the Sabbath Branch dedicated to Medical Research, who was inspired by a kindly human doctor she encountered who only cared about healing the sick even though he'd been exiled and hunted by his own country. It's called Pharmacomancy and is a bit more like a magical version of real medical procedure than traditional white magic. There's also a more "traditional" style called Hieromancy, which is the type of magic that can be used by the servants of the gods through borrowing their power, but it focuses more on buffs and light based attack magic than healing and tends to vary depending on which god the caster serves, the most common and well known being the Hieromancy of the Chief God. The hieromancy of the Fallen God subverts this however. All of the Fallen God's Hieromantic spells are either corrupted versions of the Chief God's or are meant to be used to corrupt people into her followers.
  • Wife Husbandry: Echidna have the ability to innately sense when a human child is destined to awaken as a hero. Sometimes when they discover such a human child they will assume the form of a human woman and raise or train him themselves for the sake of turning him into their ideal husband.
  • Wicked Witch: The Dark Mage is referred to as such and fits the trope in personality and general behavior, but not so much in looks. They're described as selfish, self serving and anti-social monster girls who spend most of their time cooped up in a cottage in the woods or wizard's tower pursuing the Arcane arts alone unless they're pursuing a man. When they do have a man in their sights they'll resort to any means necessary to ensnare him, even magically enslaving entire villages to get to him if they must. Naturally subverted entirely by the Witches of the Sabbath.
  • Witch Species: Both an entire race of Cute Witches who work for the Sabbath under the Bahomet and the more independent and buxom Dark Mages.
  • World of Buxom: With the exception of child-like monsters and various others, many monsters are well-endowed, with C-cup breasts being small among them.
    • Even humans have the advantage of this. Many of the women whose pre-monsterized forms were shown have large breasts, though slightly behind their monsterized forms.
  • Wutai: The Zipangu region, which is the native land of all monsters based on Japanese mythology, as well as humans who fashion themselves after Jidai Geki. The monsters are even referred to as "Youkai" there, as opposed to just "Monsters". They range from being tolerated, to welcomed, to even revered by the humans who live there - and vice versa. They seem to be the third option of the Black and Gray Morality of the setting, but sadly don't seem too interested in the struggle between the Order and the Overlord. Rather they have built up their own forces to keep other powers from interfering in their part of the world (namely having stopped an invasion from an Order-aligned nation in the past). Further information has also shown that while they do not actively serve the Overlord, they are not against her either as it is thanks to her that they have become able to live even closer with humans than they could before, and thus they appreciate and respect her greatly.
  • Yamato Nadeshiko: Nureonago, Yuki-Onna (who even wears a kimono), Shirohebi and Kikimora, among others.
  • You're Drinking Breast Milk: The Holstaur's breast milk is said to be "both delicious and nutritious" and apparently sells well among both humans and monsters.
  • You Gotta Have Blue Hair: Mermaid, Succubus, Sea Slime, Beelzebub, Pixie, Jinn of the Jar, Medusa, Sea Bishop and Nereid.
  • Yandere: Downplayed, as no monster would actually kill others to claim a man, let alone bring harm to their husband. Some do play up certain aspects common to Yanderes, though. The Will-o-the-Wisp is one example. While some monsters involuntarily trap a man (like a Jinn of the Jar), the Will-o-the-Wisp actually imprisons her husband in her cage to the point that not even their soul can escape after death. They're also very jealous and cannot stand it if another couple's happier than her, actively competing to outdo them with their own husband. Oomukades, giant centipede monsters, are noted for rather obsessive displays of affection.
  • Youkai: The monster girls of the Zipangu region. Thanks to various circumstances that allowed their evolution to diverge from the rest of the world, they've had an uneasy coexistence of sorts with humans since even before the current Overlord came to power. Unlike many of the other monsters, youkai aren't part of the Overlord's Army, and, since Zipangu isn't under the influence of the Order, there are no Knight Templar hunting them down (though invasions from anti-monster kingdoms have been attempted and failed, and some of the more fearsome youkai are sometimes hunted or excluded). In fact, powerful youkai like nine-tailed Inari are often revered there as gods. The comparative lack of hostility has allowed many monsters to develop into less ferocious versions of mainland monsters, relying more on seduction and even friendship to gain mates as opposed to outright assault.