From publisher blurb:
This generator makes it easy to generate huge dungeons which stretch out both vertically and horizontally, with different entrances, connections between areas, factions of monsters and their relations. Begin the exploration if you dare, but be warned: you will get lost.
This supplement contains:
2 pages to generate the megadungeon’s cross section, which consists of Areas and Levels (and the links between them),
2 pages to generate Levels with corridors (length, features, end) and rooms (size, shape, type of content, chance of treasure, doors),
2 pages about monsters (level, types of monsters, factions & their relations, wandering monsters),
5 pages with a detailed example going through all the steps,
1 printable megadungeon cross section template