Devildom

The Devildom is one of the three worlds that exist 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, though 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. Beelzebub often eats here.
 * Hocus Pocus - a shop that specializes in magical items and such. Satan often shops here to prank Lucifer.
 * Akuzon Delivery Center - a shipping center where Leviathan often purchases his anime or gaming goods from.
 * The Fall - a popular nightclub that Asmodeus frequents and often use for celebratory occasions.
 * Majolish - a clothing store that Mammon, Asmodeus, and sometimes MC will shop at that offers designer clothes.
 * The Royal Library
 * The Mausoleum
 * Ristorante Six - a fancy restaurant visited in-game.
 * Cat's Eye - a restaurant mentioned in-game.
 * Goetia - a hair salon that Asmodeus goes to.
 * Headless Café
 * Madam Scream's - a popular bakery.
 * Diavolo's Private Beach - a private beach owned exclusively by Diavolo where it has an artificial sun.
 * Hell's Burger
 * Hell Supermarket
 * Hell Dome - Likely a structure that holds events such as a sweets fair.
 * The Devil Planetarium
 * Le Pluvier - a restaurant mentioned in anime short.
 * Le Diable - a restaurant mentioned in anime short.

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.

Currency
The currency used in Devildom is called Grimm which can be gold coins with a skull, or brown banknotes. The player also uses this currency for various expenses in the game; upgrading cards or unlocking spaces in the devil tree cost Grimm. Players can obtain Grimm by clearing battle stages or sending characters to work at D JOBS. Tasks and pop quiz events also often include Grimm as rewards.

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.

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.
 * This is due to the previous misuse of their free availability, which is strongly implied that Mammon was the perpetrator.
 * 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.
 * The names of some places in the Devildom are based on parts of real-life languages and titles.
 * "Akuzon" is a play on the enterprise Amazon and "akuma" (悪魔), which is Japanese for "devil".
 * "Majolish" comes from "majo" (魔女), the Japanese word for "witch".
 * 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.
 * It does rain in the Devildom, as seen in the devilgrams Cooking on a Rainy Day and Shelter From the Rain.
 * In Lord Diavolo's Fast Food Adventure, there's an AkuDonald's, which is a parody of McDonald's.
 * In Star-Crossed Lovers, an autumn sky constellation is mentioned — the Pool of the Abyss — along with the myth associated with it.
 * One star represents a beast, and another the maiden that was carried off by it. The nebula below the two stars symbolises the pool created by her tears as she yearned to see her beloved.
 * In Demons Catch Colds?! it is revealed that demons can get sick and can catch Devildom cold — a mild seasonal sickness, equivalent of human common cold.