Devildom

The Devildom is one of the three worlds mentioned in the game. It is where demons reside and where the majority of the game takes place. The Devildom is a distinctly different realm from Hell, presumably existing in a plane just above it.

There are eight layers to the Devildom, and as mentioned during the normal story mode, the Demon King -- Lord Diavolo's father -- lies willingly dormant at the very bottom. Due to this, Lord Diavolo rules as the de facto king of the Devildom.

In the Devildom, there is no sunlight. The world exists in a constant state of darkness at all times and according to Diavolo, there are different degrees of darkness depending on the time. Despite this, demons still adhere to a "day/night" schedule where they sleep and are expected to awaken in the "morning" as evidenced by the fact that the demon brothers often sit down together for breakfast and dinner as well as go to sleep and attend school/work at specific times. In a text from Asmodeus, its alluded that there are four seasons in the Devildom despite the lack of a true day/night cycle. From this text, it can be assumed that the seasons function the same or at least similar to the four human world seasons, although currently (up to Lesson 16) there is no canon evidence of this aside from the text from Asmodeus.

Known Locations

 * House of Lamentation - the seven demon brothers' home, MC moves in with them at the beginning of the story.
 * Royal Academy of Diavolo (RAD) - the Devildom's school, the game's characters attend it.
 * Demon Lord's Castle - Diavolo's residence.
 * Purgatory Hall - dorm for exchange students; Simeon, Luke and Solomon live here during their stay in the Devildom.
 * Hell's Kitchen - a casual restaurant with a bar visited in-game; one of the sites for Jobs.
 * Hocus Pocus
 * Akuzon Delivery Center
 * The Fall - a popular nightclub that Asmodeus frequents and often use for celebratory occasions; one of the sites for Jobs.
 * Majolish
 * The Royal Library
 * The Mausoleum
 * Ristorante Six - a fancy restaurant visited in-game; one of the sites for Jobs
 * Cat's Eye - a restaurant mentioned in-game
 * Goetia - a hair salon that Asmodeus goes to.
 * Headless Café
 * Diavolo's Private Beach - a private beach own exclusively by Diavolo where it has an artificial sun.
 * Hell's Burger
 * Hell Supermarket

History
In Lesson 30-1, Satan and Simeon expand on Devildom history. The Devildom came into existence alongside the Celestial Realm and exists in tandem with it. Shortly after its creation, a primeval forest covered the entirety of the Devildom.

Food and Drink
Eating in Devildom is a sometimes dangerous experience, as some foods are too strong, too dangerous, or otherwise inedible for MC. The rest of the Student Council looks out for MC in this regard, but there is also mention of food from the human world. It seems that there is some mixing of foods or foods inspired by the Human World.

Drinks

 * Demonus: One of the Items MC can offer from the special event purchases, an intoxicating drink for demons, but doesn't have an effect on MC.
 * Barbato's Tea: One of the Items MC can offer, favored by Diavolo, and Lucifer likes it as well.
 * Black Coffee of Melancholy : One of the Items MC can offer.
 * Paradise Blue: One of the Items MC can offer, Simeon's favorite drink, but Mammon likes them too.
 * Little Devil Mango Slushy
 * Bufo Egg Milk Tea: Leviathan's favorite drink which happens to to be popular with succubi.
 * Chaos Devil Cider: Mammon likes to mix it with ginger ale.
 * Orange Acid: Leviathan likes to mix it with ice tea.
 * Shadow Coffee: Lucifer likes to mix it with bitter oolong and black tea.
 * Red Coffee
 * Hell Coffee: Known to become bitter when the person who brews it has feelings for the someone who they’re brewing for. Seen in Lucifer’s chat Bittersweet.
 * Hellfire Rose Tea
 * Fermented Milk from a Half-Dead Cow : One of the choices in the TSL Quiz.
 * Sparkling Fresh Bloody Soda

Fruits

 * Princess's Poison Apple: One of the Items MC can offer, Lucifer is fond of these, but Leviathan and Asmodeus likes them too.

Snacks

 * Instant Noodles (Hell-Sauce Flavor): One of the Items MC can offer, Mammon's favorite food and will try to cook this for dinner (if MC lets him).
 * Spicy Newt Chips: Beelzebub likes them.
 * Comfort Candy: One of the Items MC can offer.
 * 666 Fries
 * Shadow Chocolate-Dipped Donut
 * Demon Zebra Churros
 * Black Potato Tornado Fries
 * Spider's Web Cream Puffs: a teacake that Barbatos prepares for MC
 * Ghost Pumpkin Cream Puffs: a Halloween-exclusive treat at Madam Scream's that Beelzebub invites MC for.

Meals

 * Family Pack Sushi: One of the Items MC can offer, Belphegor enjoy this tray (minus wasabi). Beelzebub likes it as well. According to the text "Sushi Cravings", there are shadow hog, devil salmon, grilled vampire, bufo toad, devil zebra meat, and devil moray.
 * Spicy Rainbow Pizza: One of the Items MC can offer, Leviathan prefers this pizza, but Satan likes it too.
 * Fried Scorpion Sandwich (with vinegar and tartar sauce)
 * Red Spider Sandwich
 * Backstabbing Sandwich: One of the Items MC can offer.
 * Pasta with Mixed Entrails, Sliced Anaconda, Fried Tarantula, and Nile Crocodile Brains.
 * Cursed Goat Tartare Sandwich with Cheese: The Lord of Flies favorite food.
 * 500-year-old extra sticky fermented beans: One of the choices in the TSL Quiz.
 * BLT Devil Sandwich : Simeon's specialty
 * 4,000-year-aged Cheeseburger.
 * Shadow Goose Burgers
 * Shadow Swine Offal
 * Grilled Snake
 * Quetzalcoatl Brains : Belphegor's favorite food, which can be used in various recipes like sushi for example.
 * Whole Roasted Havoc Devil
 * Vjedogonia Bile Soup
 * Shadow Goose Meat and Egg Lasagna
 * Mixed Belladonna and Poison Hemlock Greens with House Dressing
 * Sautéed Wild Hare Liver
 * Gigadeath Burger
 * Purgatory-style Basilisk Boil
 * Devildom Stir-fry with Toxic Chameleon
 * Pot-au-feu with locally-sourced Devildom Vegetables and Flame Mushrooms
 * Grilled Orthrus
 * Demonkiller Remora Carpaccio
 * Borscht with Boiled Centaur Gizzard
 * Flaming Hot Fafnir Stew : A dish which is similar to Beef Stroganoff.
 * Stonefish Meunière with Little Devil's White Sauce.
 * Roasted Roc : Similar to roasted chicken.
 * Fried Shadow Bat
 * Hellfire Curry Rice
 * Shadow Hog Ramen
 * Fried Devil Chicken
 * Poison Bleu Cheese Hamburger
 * Hellfire Mushroom-filled Soup
 * Babylon Curry
 * Simmered Behemoth's Hind Leg
 * Double Poison Cheeseburger

Desserts

 * RedxRed Apple Pie: One of the Items MC can offer, Satan enjoys these.
 * Wicked Cupcake: One of the Items MC can offer, Asmodeus likes these, but Satan likes them too.
 * Madam Scream's Macarons: One of the Items MC can offer, Barbatos's favorite treat.
 * Barbatos's Signature Cake: One of the Items MC can offer, Luke loves them, but Lucifer and Asmodeus will eat them as well.
 * Pitch-Black Shortcake
 * Lunatic Pudding: a pudding that Diavolo likes to eat with a warning that a human consuming it will produce pheromones that potential mates find desirable for 24 hours. Seen in the Devilgram Enchanted Pudding.
 * Mango-Flavored Little Devil’s Gelatin Parfait
 * Snow Beary: Headless Café’s exclusive item only available in the summer. It was also seen in the anime “Polarbeary Café”.
 * Hellfire Mushroom Rolled Cigar Cookies: Diavolo's favorite treat.
 * Babel Parfait
 * Hell Cream Cat Tongue Cookies
 * Ultra Monster Parfait: The largest Parfait in the Devildom.

Trivia

 * It is presumed that the Devildom's time schedule exists in the same 24-hour rotation that the human world adheres to due to the fact that MC's D.D.D. is set to a 24-hour clock
 * There are several ways to get out of the Devildom as per Lesson 11-4:
 * One of several "external magic seals" that work as passages between worlds
 * All demons aside from Lord Diavolo, Barbatos, and Lucifer must receive "permission in advance" before they can use the seals due to the previous misuse of their free availability, which is strongly implied that Mammon was the reason for limiting the use of seals.
 * Considered the "classic route", an individual can walk through all eight layers of the Devildom on foot, however, it is considered "too long" and, as Lucifer mentions, would destroy MC's psyche.
 * Witches or sorcerers can also summon individuals out of the Devildom, though there are alluded consequences to this method.
 * According to Satan, books from the human world are very rare in the Devildom, especially first editions.
 * Akuzon is a play on the enterprise Amazon and "akuma", which is Japanese for "devil".
 * The moon in the Devildom is portrayed much larger than in the human world.
 * In A Special Ceremony, Lucifer mentions that New Year's is celebrated every 100 years in the Devildom.
 * In Cooking on a Rainy Day and Shelter From the Rain, it rains in the Devildom.
 * In Lord Diavolo's Fast Food Adventure, there's an AkuDonald's, which is a parody of McDonald's.