Dungeon

Dungeon (ダンジョン, Danjon) is a type of adventuring location in DMMO-RPGs. YGGDRASIL was well known to contain various dungeons for players to challenge.

Overview
In YGGDRASIL, dungeons are areas that players can enter to do some grindings as well as hunting down monsters both in terms of leveling up and acquiring items. Yet they were also not the sort that told a party what levels of difficulty were suitable for them. Discovering a dungeon could affect the world ranking of a guild. The Guild can conquer a dungeon and make it their Guild Base if available as one for the extra benefits. However, there are other kinds of dungeons that are just standalone and cannot be made into a guild base. It can then be made into a guild base controlled solely by the guild alone complete with various other means like customization, etc. through the use of Data Crystals.

In fact, clearing a dungeon often yielded a variety of different items, ranging from rare data crystals to artifacts. For example, hard-to-find dungeons that were left unexplored until discovered may contain monsters that dropped valuable data crystals. The first time one ran a dungeon, there would be a bonus, or about 10% more treasure chests. Once a dungeon was cleared for the first time, the big treasure chest would offer equipment with item levels up to 10-20% higher than usual. Clearing the dungeon under certain conditions can even be awarding like being granted a World Item.

On the other hand, beating trash mobs and the environment made up 40% of the difficulty of raiding a dungeon, while as beating its boss was the other 60%.

Not only that, but the location of a dungeon does tend to vary in design and terrain environmentally. Some dungeons can only be found under certain conditions and one needed special equipment to delve into it there. For instance, the entrance to a dungeon amidst a field of flowers in the depths of a forest can only be seen under the light of the full moon. A notable example of this is the Frozen City in Niflheim which can only be entered during a blizzard. The proper way to clear these dungeons was probably to learn which bosses would get stronger, and in which order. Then, the parties would simultaneously enter their boss fights and beat them at the same time.

Also, dungeons ranged from different types such as the Great Tomb of Nazarick, a simultaneous attack dungeon. Many people hated simultaneous-attack dungeons, also known as "die-by yourself dungeons." Dungeons of this caliber required several parties working in unison along different routes to complete and were typically designed so that everyone would meet up at the boss room, whereupon they would face the raid boss together. There are even dungeons with higher difficulty than just Nazarick. Particularly, Tabula Smaragdina stated that invading one of those unnamed dungeons will require the cooperation of 36-man parties (a legion) and two guilds combined.

While at the same time, some dungeons out there were designed to allow anyone to enter, so their doors and interiors would expand to accommodate tall and bulky people. This way, they could hold big monsters and remove the chance of said monsters being stuck behind terrain and slowly chipped to death from a distance. And of course, some players were enamored of the benefits of growing bigger — their attack radius would increase and the amount of damage dealt would increase depending on how much larger one was than one's opponent.

In response to this reasonable concern, the developers' response was to prohibit the scaling of the dungeon according to the monsters' size, so even if one entered a room while enlarged, the room would stay the same size. However, with these restrictions in mind, one could make passages that nobody could pass through, creating impregnable strong points for a guild base. The dungeon rule system 'Ariadne' was hard-pressed to deal with situations like that.

Fortunately, the solution was simple since players or monsters can equip an item that would allow anyone to go through those passages. For starters, there exists the Ring of Ainz Ooal Gown that allows oneself to transverse between different floors of a dungeon controlled by a guild.

Rules
YGGDRASIL has many unexplored dungeons within the Nine Realms. Plus, there is always fierce competition to discover and clear them. The first time the players enter a dungeon, they will be granted a bonus of about 10% more treasure chests find. Also, the first time a dungeon is cleared the big treasure chest would offer equipment with item levels up to 10-20% higher than usual.

While dungeons seem impenetrable and impossible challenges, they are quite the contrary. Conquering a dungeon is a great undertaking that seems only a powerful guild can manage. Once occupied by the guild, the design, defenses, and appearance of a dungeon can be altered to suit the needs and taste of the guild members.

In order to achieve this, several factors need to be included such as the necessary skill in programming for making alterations in the area; sufficient data crystals to add additional features and even gold to finance the special effects of those areas. Additionally, another factor that needs to be considered for a guild controlling a dungeon is to ensure that it must meet the specified laws enforced by the programmers and administrators of YGGDRASIL.

Clearing a dungeon often yielded a variety of items, from rare data crystals to artifacts. However, clearing a guild base dungeon merely gave the owner’s rights. The guild could only own one guild base-type dungeon at a time. If they wanted to claim another dungeon, they would need to relinquish their claim on their present one.

If it is a guild base-type, the Ariadne system specifications required that there be a continuous path from the entrance to the heart of the dungeon. They would also measure the distance traveled within the dungeon, the number of doors one had to pass through, and many other categories, all in exacting detail. When a dungeon does happen to violate these requirements, such faults are later uploaded to YGGDRASIL. Afterward, a penalty would be levied and a lot of funds would be deducted from the guild that is in possession of the dungeon. For that reason, dungeons owned by guilds who went against the game's rules would be flagged by the YGGDRASIL system and fined for it.

List of Dungeons
Dungeons are usually served as a potential territory of being the home base for guilds. With that said, dungeons have levels that are directed towards NPCs. Out of all the dungeons, only one dungeon for each world in YGGDRASIL is said to have the highest amount of levels possessed, which were 3000 levels at most.

In DMMO-RPGs like YGGDRASIL, one could place pop monsters like a Carrion Baby within dungeons by paying the appropriate in-game or real-world currency. However, they would not come back to life after being destroyed, so they were more of a luxury to players.
 * Great Tomb of Nazarick: It is ranked as the top dungeon in YGGDRASIL. The base amount of levels was originally 2250. If the guild conquered this dungeon during their first try, they gain an additional 500 levels added as a bonus to its original amount would equate to about 2750 at max.
 * Frozen City: It is a special event dungeon that could only appear during a blizzard in Niflheim.
 * Fake Nazarick: A copy of the Great Tomb of Nazarick built within the Great Forest of Tob.
 * Mine Dungeon: It is a Mass for the Dead dungeon built by Demiurge as a diversionary tactic to make the mines avoidable to humans.
 * Underground Tomb: A training dungeon built by the Sorcerer Kingdom close to E-Rantel for the adventurers.

Trivia

 * For Nazarick, the Ariadne System was solved by the 5th and 6th levels, which involved a lot of gold to widen the dungeon to maintain it.
 * Ariadne is a character from Greek mythology, most famously in the Minotaur myth, assisting Theseus in navigating the labyrinth.
 * There was actually a simple way of creating an invincible fortress-like dungeon: By sealing the entrance, no one would be able to get in.
 * Clearing an unknown dungeon which was not far below the recommended level was unheard of in YGGDRASIL.
 * Apart from the Great Tomb of Nazarick, there were many dungeons in YGGDRASIL that prohibited escape by teleportation.