Light Novel / How Not to Summon a Demon Lord

The MMORPG Cross Reverie had one player who was stronger than everyone else, earning him the nickname of "Diablo, the Demon Lord". In real life, however, he is Takuma Sakamoto, a boy with No Social Skills. One day, he gets sucked into another world, but with his appearance as Diablo instead of his normal form. There, the two girls who summoned him cast a spell on him to enslave him.

However, Takuma has a skill from Cross Reverie that reflects the magic back onto the girls, enslaving them to his will instead! Panicking, Takuma says to them "I'm amazing you say? Of course, I am. I'm Diablo... The one feared as the Demon Lord!"

Stuck in another world, Takuma (as Diablo) has no choice but to go on an adventure with his newfound companions.

An Anime TV series produced by Ajiado Animation Works and directed by Yuta Murano premiered on July 5, 2018. Funimation's Simuldub of the anime series premiered on July 25th, 2018. Watch it here or subbed on Crunchyroll here. A second season of the anime, now animated by Tezuka Productions, premiered on April 9, 2021 on Crunchyroll.

How Not to Summon a Demon Lord provides examples of:

• Adaptation Expansion: The anime covers things that neither the manga nor the light novel do. Like the fact that the reason Diablo's got No Social Skills is that he's been shunned, for basically no reason, since he was a small child.
• All Deaths Final: Diablo learns that while resurrection spells are common in Cross Reverie, they don't exist in this world and the dead stay dead.
  • Volume 10 introduces "Thanatos the Immortal" who seems to avert this when he was killed gorily by Europa but shows up moments later fine.
• Animal Eye Spy: The <Turkey Shot>, a summoned beast that is weak offensively but has the Skill to let the <Summoner> see what it sees.
• Bizarre Sexual Dimorphism: Kobolds. Their females look like dwarves, albeit with fox rather than dog features, but the males all have the heads of foxes.
• Black-and-Grey Morality: Volume 12 introduces the Gelmudo Empire, which is morally pitch black, and is so heinous, they make the Fallen, at their worst, look downright benevolent by comparison.
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• Call-Back: In the fourth novel, Rem strongly advises Lumachina to spill the beans at once about her situation, lest she "will invite a situation upon herself that she will never forget throughout her whole life." This hard-earned bit of dubious wisdom comes the time when Diablo "tortured" her into confessing her problems back in the first novel by teasing her cat ears into an Immodest Orgasm.
• The Cameo: The original broadcast version of Season 2 episode 2 features a quick cameo of hololive's Pekora Usada. She's color swapped, but still wears her trademark pigtails and hair carrots.
• Cerebus Syndrome: While the story was never full of sunshine and rainbows, in Volume 12, things get real dark, real quick, with the introduction of the Gelmudo Empire, who use Child Soldier elites, the racist human commanders literally stomping their heads into the ground until they bleed, for the slightest insubordination or failure, real or imagined, with the army bent on conquest, enslaving all they run across, and run by an Immortality Seeker Emperor on his deathbed, desperate for results to capture a certain Pantherian...
• Chekhov's Gun: The potions Diablo makes with Shera end up being used in Episode 12 to save Rem's life.
  • When Rem teaches Shera how to summon Turkey Shot, she also gives Diablo a magic stone used for contracts. This becomes useful when he tries to find a way for Klem to be allowed in Faltra - by using the enslavement contract on her.
• City of Adventure: By design. The city of Faltra is on the frontier between the Human kingdom, several demi-human races, especially elves, and the Fallen. A second one ends up being Zircon Tower City, where desert adventures regularly venture out to the sands, risking life and limb for precious treasures buried in forgotten tombs.
• Double Standard: Rape, Female on Male: In both Volume 8 and 11.
  • Volume 8: Raphlesia corners Diablo, on his wedding night, and starts coming on to him, strongly, as "thanks" for saving her life in the wake of Demon King of the Heart Cardia fiasco, despite his protests, and the fact that he's already married to Shera and Rem. Rem chances upon it and is enraged, to the point that she doesn't speak to him for a full week afterward.
  • Volume 11: Diablo gets accosted by Rem's aunt, who promises to teach him a secret clan technique, that he was already starting to figure out after she deflected one of his spells with her bare hands, and starts by putting his hands on her breasts, which isn't too different from the manner in which he learned Aura Vision with Shera. Unfortunately, this is just a trick she used to get his guard down so she could literally paralyze Diablo, by magically short-circuiting his nervous system. Then she proceeds to strip his pants and performs oral sex on him, against his will, even acknowledging it's wrong to do so, but treating it like a harmless prank. "Hee Hee! As Rem's oneesan, I shouldn't be doing this, no?" Shortly after the deed is done, Rem walks into the area, not angry, not ranting, raving, or violent. She just simply divorces him, on the spot, leaving him completely speechless.
• Elemental Powers: The Elemental Magic system found in both Cross Reverie game and the world Takuma was summoned to. The game favors the system, while the world looks down on it.
  • Casting a Shadow
    • Gravity Master
    • Power of the Void
  • Blow You Away
  • Dishing Out Dirt
  • Light 'em Up
  • Making a Splash
    • An Ice Person
  • Playing with Fire
    • Having a Blast
• Elfeminate: Some of the male Elves such as Celsior.
• Enemy Civil War: The Fallen actually don't get along with each other very well. The only thing that makes them combine their efforts is their hatred for the Six Races. The members of the Vhal faction are little more than mindless beasts who attack the six races on sight without plan or preparation, and if they don't have the opportunity to attack just blend quietly into the forest that is their home. The "moderate" faction is desperate to wipe out as many of the six races as they can, but only strike when they believe they have a winning strategy in place. While the Edelgard faction doesn't care for the six races very much, they're content with "live and let live" if they're not directly antagonized, and seek only to serve the Demon Lord. The last two really don't like each other and have come to blows, repeatedly.
• Expanded Universe: The new world. At first glance, it possess the same elements as from the game Cross Reverie that Diablo is familiar with. However, he later discovers that it possesses elements that weren't in the base game, such as Keera's mind control flute and the Force Hydra, or Rose's offensive abilities. This leads Diablo to the conclusion that every planned element from Cross Reverie is in the new world.
• Fantastic Arousal: Not only does Diablo accidentally discover that Rem (like presumably most Pantherians), have very "sensitive" ears, but when volume 3 rolls around, part of the process involved trying to remove the slave collars that Rem and Shera accidentally got by having their summon contract on Diablo rebound, involves manipulating and inserting mana into others. His reluctant model, Shera, has an interesting reaction, and later puts Rem through the same experience.
  • Klem's horns later turn out to have a similar effect.
• Fantastic Racism: Appears in both Cross Reverie and the other world. In the game, it is more of a background setting. In the other world, it is a reality that some of the Humans discriminate against Demi-humans.
• Fictional Video Game: Cross Reverie, the MMORPG that Takuma played and often references to compare the world he was summoned in.
• Fighter, Mage, Thief: The main job classes of adventurers in both Cross Reverie and the world are "Warrior", "Sorcerer", and "Archer". They have further derivations depending on what they specialize in.
• First Town: In Cross Reverie, the first town is the Royal Capital Sevenwall.
• Formula with a Twist: The series is based on the twist that the protagonist is only pretending to be a Demon Lord. He is exceptionally powerful in the new world, but being called a Demon Lord in the first places was only an Appropriated Appelation he used while playing his MMORPG.
• Funny Background Event: In episode 12, after Sylvie susses out that the little blonde girl traveling with them is Krebskrum reborn, Emile spends the rest of the conversation standing in the background, unmoving, rigid with shock, and sporting a pair of Blank White Eyes.
• Godlike Gamer: Takuma fit this to a T. In the MMORPG "Cross Reverie", he played as the Demon Lord Diablo, who was so ridiculously skilled and powerful that no one dared to challenge him. In fact, he decided to hold back in order to keep things fun for himself. Then he's cast into said world where he's reincarnated as his character and finds everyone else is laughably underleveled.
• G-Rated Sex: Subverted. The process to separate Krebskulm's soul from Rem first appears to simply involve giving Krebskrum large amounts of mana. Unfortunately, to give the mana to Krebskulm, and not to Rem, Diablo has to remove Rem's panties and insert his finger somewhere very, very delicate.
• Gray-and-Grey Morality: Surprisingly enough. While the Fallen are shown doing some terribly nasty things, at least on the battlefield, they are fighting for their very survival from extremists like the Holy Knights, and if there's no reason to fight, some like Edelgard's faction, are perfectly content with being civil, polite, and happily tolerating peaceful coexistence. However, that only constitutes a small minority of the Fallen, most of whom want nothing more than the genocide of the six races. The six races also aren't shown to be much better, with Fantastic Racism in every possible direction, banditry, slavery, although highly idealized, and horrifically brutal Knight Templar General Ripper "Holy Knights" that have carte blanche to declare anyone "guilty" of being a Demon Lord Worshiper, resulting in inflicting Torture for Fun and Information and then "granting them salvation" by killing them, at the level of entire towns! Thankfully, the Holy Knights and the Church as a whole are successfully reformed later in the light novels (if only due to all the corrupt officials being wiped out by that point).
• Half-Human Hybrid: Noted to be basically nonexistent. It's said that the six races cannot interbreed. There is a way around that, however.
• Happiness in Slavery: When Diablo is introduced to a slave trader, the slaves are universally happy, and healthy in both mind and body. His two traveling companions Rem and Shera grow accustomed, and even fond of their slave collars that resulted from a magic accident, to Diablo's internal dismay, and the law of the land is that abusing slaves is a felony with harsh, undisclosed consequences. Even patrons to a legally sanctioned slave tent require a screening and a referral from a renown and reputable town authority and are considered equivalent to patrons looking to buy a beloved pet, not someone seeking to exploit people. Although it is often noted that there are illegal slave-traders in the setting as well. In-universe, this is highlighted as roughly being the equivalent of the difference between a pharmacy dispensing medicine with a valid prescription, and the way drug dealers operate.
• Hero's Slave Harem: One of the Trope Codifiers. When Diablo is summoned, his ring that deflects all magic reverses the slave spell that the two girls who summoned him had used and thus makes them his slave instead of the other way around. At first, no one is happy with the arrangement and look for ways of reversing the spell, but after Diablo shows himself to be a Nice Guy underneath his Jerkass Façade, the girls fall in love with him. He acquires more girls later (some, though not all, being slaves as well).
• Humongous Mecha: The pillar of Gelmudo's war-machine.
• It Makes Sense in Context: Diablo describes his situation in the fourth novel thusly:
  Like this, Diablo misrepresented himself as God for the sake of biscuit expenses and avoiding marriage.
• Imagine Spot: Diablo has a few where he pictures himself and other characters in scenarios set in his original world.
• It Always Rains at Funerals: Three days after the Fallen's assault on the city, the funeral was held for all the adventurers that were killed by Grigore and appropriately enough, it was raining.
• Killed Off for Real: In Cross Reverie, the worst that can happen to a player when they are killed is a level-down penalty and a re-spawn at the last town they visited. In this world however, death is permanent. As such, very few people would be willing to risk their lives to fight stronger monsters. Diablo also concluded this is what contributed to the circulation of what he considers low quality spells, skills, and weapons as well as the promotion of the Summoner class since it is the easiest and safest class to learn as a sorcerer and allows a higher chance of surviving a quest.
• Language Barrier: Kobolds and most of the "mortal races" can't understand each other, at all. The kobolds sometimes trade with dwarves, but humans treat them like wild beasts and try to drive them out of areas they settle and make towns in.
• Little Bit Beastly: Three of the six races: Dwarves have dog ears and tails; Pantherians have cat ears and tails; Grasswalkers have rabbit ears and tails. The more humanoid of the Fallen have animal traits as well, usually on the reptilian side.
• A Magic Contract Comes with a Kiss: The slavery ritual for summoned beasts.
• Magic Is Mental: To cast spells, you have to think about what their game description describes, i.e. to cast <Explosion>, Takuma has to imagine "Gathering hydrogen from the surrounding air and igniting it with magic".
• Magikarp Power: Elemental mages are considered useless and pathetic, because they, like most people, avoid fighting whenever possible, so they never reach the point where they begin getting powerful spells.
• Marry Them All: Diablo marries both Rem and Shera in Volume 8 of the light novels. (Although, there is a little mix-up with the rings to where Rem had technically married Shera instead of Diablo that takes a couple more volumes to correct.)
• Media Transmigration: Takuma Sakamoto is a shut-in Godlike Gamer who dominates the MMORPG called Cross Reverie as a character known as Diablo the Demon Lord. But then one day he gets sucked into a world resembling Cross Reverie, where he becomes his own overpowered player avatar Diablo.
• Men Are the Expendable Gender: Male antagonists are generally far less sympathetic than female antagonists, and far more likely to end up dead. In addition, there are very few male protagonists aside from Diablo himself.
• Meta Guy: By nature of being from the real world, Diablo is aware of game quirks, and constantly lampshades various game tropes or comments on how things work for him in the game versus the game world.
• Mugging the Monster: Most of the antagonists go and provoke Diablo, or his companions, without knowing anything about them, finding out too late that they're way outclassed. It eventually segues into Bullying a Dragon and Too Dumb to Live because people still go out of their way to provoke Diablo when his power, intelligence, competence, and tendency to brutally beat down people who threaten him and his companions becomes well known.
• New Life in Another World Bonus: Diabolo possesses his MMORPG Cross Reverie's avatar granting him all of its abilities including his counter-stop level 150.
  • His most used equipment being The Demon Lord's Ring, a drop from defeating the Demon Lord of the Mind, Enkvalos, working as an absolute Attack Reflector against anything classified as magic. The only downside is that it also reflects positive magic cast on him such as healing and status buff spells.
• Noodle Incident: One thing the story never explained so far is how Rem and Shera both came to be at the Starfall Tower.
• Our Demons Are Different: There are at least four classifications:
  • Demon Lords: Absolute forces of evil that were separated into pieces and sealed away long ago.
    • While Diablo claims to be one himself (from another world), he's actually just performing a huge roleplay bluff.
  • Demonic Beast: Monsters in the wild.
  • Fallen: An intelligent race that is depicted as antagonistic to the six races and subservient to the Demon Lords.
  • Demons: One of the six races. They look like humans with tattoo markings that are said to be descended from the Fallen.
• Overdrawn at the Blood Bank: Played for some VERY dark laughs at the Adventurer's Guild. Instead of just signatures, the guild requires you to also sign your contract with blood, obtained via a knife. Diablo tries to cut slightly, ends up going to the bone, and spraying a poor guild clerk, the counter, the wall behind her, and over half of his contract with blood. In the next shot inside the Guildmaster's office, she's seen holding the contract, which is now soaked completely red from the bottom half.
• Pragmatic Adaptation: The manga and anime adaptations omit, move, and alter some events from the light novels.
• Readings Are Off the Scale: There is a mirror that measures people's Power Levels, measured by how much of your image you can clearly see in it. When Diablo tries it, he's too powerful, so it malfunctions and shuts down. In the anime, it's portrayed as causing the entire area around the guild to suddenly go dark after a bubble of red lightning-like streaks expands from the now pitch-black mirror.
• RPG-Mechanics Verse: The world that Takuma was summoned to that is similar to the game Cross Reverie. It has levels, skills, and other things from the game.
• Separated by a Common Language: The light novels and English anime sub use the British term "biscuit" to describe Klem's favorite food, whereas the English dub of the anime goes with the American term of "cookie".
• Shout-Out:
  • There is a scene in Volume 6 where Diablo wishes he could Return by Death.
  • A palette-swapped Expy of Usada Pekora appears as a background character in the original broadcast version of Season 2 Episode 2.
• Slave Collar: Slaves and contracted summoned beasts wear magically conjured ones. It's an early plot point that both types are almost indistinguishable from each other, making people assume Rem and Shera were Made a Slave.
• Space Compression: Present in the game of Cross Reverie, but not in the world versions. As a result, a distance that would take three minutes to walk in Cross Reverie takes three hours in real life.
• Standard Fantasy Races: In the Cross Reverie game there are six races players can choose from. In the other world, the six races are the main tribesmen that populate the world. The Races are:
  • Humans
  • Dwarves: They have the addition of having dog ears and tails.
  • Elves: Pointy long ears, very commonly slender to the point of androgynous.
    • Dark Elves: Similar to Elves but have darker skin. Females have giant breasts.
  • Grasswalkers: Small childlike rabbit-eared and -tailed.
  • Pantherians: Cat-eared and -tailed.
  • Demons: Tattooed humanoids said to be descended from the Fallen. The game has them physically weaker, but they do have high INT.
• Summoning Ritual: In both the Cross Reverie game and the world, <Summoners> get summoned beasts by going to <Starfall Tower> and performing a ritual then make a slavery ritual.
• Summon Magic: A magic system found in both Cross Reverie game and the world Takuma was summoned into. The game looks down on summoning, while the world favors it. The game considers it weak, while the world puts the safety of the <Summoner> in high regard.
• Teleportation: A magic both in Cross Reverie and the other world. In the game, it is a bit common. In the other world, it is mostly just rumors and not used by the masses.
• Thirsty Desert: Zirconia, the setting of Volume 4, is this. Alongside the dangerous sand whales, the lack of water, and state of the management at the only (relatively) safe settlement in the area, Diablo's personal dungeon also ends up here.
• Too Hot for TV: A variation; the first season of the anime was officially released for free on Youtube, but was taken down shortly afterwards because it was too sexy and broke some of the rules.
• Translator Microbes: For some reason that is never explained, Diablo not only understands every word said to him, regardless of the language, but when he speaks back, his words are automatically translated into the language of the people he's addressing, in their minds. He cannot read nor write in any of the native languages, however.
• Trapped in Another World: Takuma was summoned in the first chapter as his Cross Reverie character Diablo.
• Trauma Inn: Deconstructed. While the game of Cross Reverie has the mechanic, in the new world, when Diablo over-used his MP, and suffered the proper loss of motivation, i.e. mental strength, the apathy didn't disappear despite him being cooped up in the inn for ten days. It took him seeing Shera in Go-Go Enslavement to snap him out of it. The second time it happened it took Sylvie serving him a strong alcohol with MP restoring properties to get him going again but in a drunken stupor he mistook her for a body pillow, pulled her close, stripped her naked, brought her to orgasm, and fell asleep with her still naked and unable to break free of his grip.
• Unequal Rites: There are two main types of magic-user, summoners and elemental mages. Summoners are near useless in Cross Reverie, while in the actual world elemental mages can barely do anything.
• Unfortunate Implications: In-universe. As is revealed in Volume 11, at the founding of the human kingdom, with Loads and Loads of Races, without even the concept of a Turing Test, humanity needed some "objective" method to tell the difference between sentient beings and animals. The method they chose? You can speak common, you're a sentient, even the Fallen. You can't, you're a "dumb" animal. Then the Fantastic Racism sets in...
• Yin-Yang Bomb: When light and dark elemental energies clash, they don't just cancel each other out, as one would expect. They amplify each other's destructive power in a manner eerily similar to a matter-antimatter explosion. Diablo exploits this in Volume 10 to deal with the volume's Big Bad.