What is a megadungeon?
Simply put, a megadungeon is a huge dungeon.
It can have hundreds of rooms, sprawling both vertically and horizontally. Actually, it doesn’t need to be cut in multiple vertical levels: they also can be areas on the same level with various themes. Interconnectivity is very important, the proof being that a megadungeon can simply be a collection of dungeons from various sources (websites, books) connected in a few points by corridors and stairs, creating this huge structure. You don’t even need to tell your players that they are exploring a megadungeon. All these independant dungeons on the world map? Add corridors between them and you have a megadungeon.
Since megadungeons are so big, it can take a lot of time to explore them, both ingame and in play time. Entering and exploring the dungeon is time consuming, but escaping it with the treasure is too, if not more, especially when encumbered. In a megadungeon, risk is bigger but reward also is (most of the time).
Some megadungeons are never fully explored, because there is always a room that wasn’t found, a corridor that is forgotten, and more importantly because the megadungeon is alive, and can change or evolve independently of the actions of the characters.
This idea is explained on the Megadungeon page of the D&D Lore Wiki:
"Unlike a standard dungeon, where it is plausible for an adventuring party to kill all monsters and recover all treasure, a megadungeon is so huge as to make this impossible. The size of the dungeon is so great that even if adventurers clear out a large section, it will be populated by new inhabitants before they can finish clearing out another. Megadungeons are commonly deadly." (D&D Lore Wiki)
It is also important to take factions in consideration when designing a megadungeon. Factions have their own motivation (expanding their territories, crushing other factions, etc.), so when the characters are in town, carousing, training or resting (which can take weeks!), they don’t stand still waiting for them to come back. Also, characters can pit factions against each other, patiently wait for them to destroy each other and then finish off any remaining monster before stealing the treasure.
Why a generator?
I always wanted to create a megadungeon but always failed to find a procedure that I liked. Plus, having a generator means that you already have the ideas (structure, setpieces, etc.) and only have to interpret them or to adapt them to the situation.
Obviously there are existing procedures to create dungeons (DMG 1e i.e.) or online generators that do that faster and which require little modification to be used (such as donjon) but I always prefer to generate things myself.
First, there is the reward of knowing that you did it yourself. It may take hours, but at least you did it. Secondly, because it’s easy to feel overwhelmed when a software gives you a dungeon with 150 rooms. You have to read it, adapt it and after all that you don’t know it as much as if you had generated it yourself.
The concept for this upcoming generator is quite simple: starting from the bigger picture, then going to the smaller details. The generation could be summarized this way:
Structure of the megadungeon: areas, levels, rooms and links
Content of each area: factions, monsters, treasure, wandering monsters
Content of each level: corridors, rooms & their content (placing previously generated monsters & treasure)
What is left to do
At the time I am writing this article, points that still need to be done are the ones related to monsters and factions.
I’m still thinking about how to choose which monsters should be in factions or wandering. And if they should be distributed by areas or by level.
Our Megadungeon Generator should come out at the end of July (if the planning doesn’t change), so stay tuned if you’re interested!