All this time I have been talking about my Medieval Fantasy game, I have yet to address what it would be about. Basically, what is the theme of this and why is it different from the majority of the other games out there.
One of the things that's always bugged me about the typical Medieval Fantasy RPG experience is the sameness of it when I feel the genre has more to offer.
Imagine a world where 'Dungeon Delving' and the 'Ecology of a Monster Ecosystem' are part of the every day life of a select few of very brave and dedicated professionals and/or those who want to be that someday. What cultural, social, economic, and political dynamics would develop over this type of addition to Fantasy Medieval societies?
Some possibilities that came to me include:
PCs set up and run a Supply Shop/Inn/Tavern inside the Dungeon. Instead of going back to town to resupply or rest up you just need to make it back to the third level of the Dungeon to get to the Player run business. This concept is actually seen in Delicious in Dungeon and it has all sorts of potential. Part of the campaign could see the PCs going into town or a near by waypoint to buy, sell, and trade what they need for their shop. There could be a rival shop run by the local Dungeon inhabitants! Maybe you need to go into the Dungeon to retrieve someone who owes big on their bar tab or had a big supply order come in.
PCs are or work for a well known Magical Component supplier - perhaps with a chain of stores - and go into the Dungeons and Fantastic Forests purely to gain such materials. It isn't their job to slay Monsters or Save the World but those who do depend on them.
A variant of this seen in Delicious in Dungeon (and further expanded with ideas of my own) is that the Dungeon might have the perfect conditions for growing certain crucial healing herbs and potion ingredients. Maybe it was even set up by the local Magic School or Wizard's Guild for that very purpose! Your party is really a group of Field Researchers seeing how the great Dungeon Experiment is doing. (In fact, if this was my campaign the Anime/Manga-themed title would be 'Dungeon Experiment' and then the name of the region or the project's creator or something).