I have to be GM tomorrow but lots of work and an little infant made me unable to sufficiently think about and prepare one part of the adventure. I was thinking that maybe you could suggest some ideas.
Here is the situation. In parallel of Tribunal 1242, some characters got involved with a Parfait Cathare, a faydit knight and a strange teenager girl, Rachel, to search for a hidding place for the "treasure of the Cathares" (which is "not of material but spiritual value").
Characters are nearby the "Pech de Bugarach", in Provence Tribunal. Since the 1970s, The Pech is famous in Provence for being a mythic place. It's also nearby Rennes le Chateau, where legends from the 19th century talk about a legendary treasure, possibly the treasure of the Cathares.
Additional informations are that the strange teenager girl actually IS the "treasure of the Cathare", as she is a direct descendant of Jesus and Maria Magdalena (legends says that Maria Magdalena finished her days in Provence after the crucifixion). As she is partly of divine essence, she has some abilities, such as to read the heart of people, comfort people and see through most of illusions. She can also banish demons, even powerful ones.
So, characters and the small cathares band are at the feet of the "Pech de Bugarach". Local tales talk about a dangerous cave system there and the cathares want to check it in case they could hide their treasure there, because they know that Montségur will soon be cast down (Montségur falls in 1243).
I would like that the discovery and exploration of the cave system be an adventure in itself. I'm searching for original ideas for this, not to make it just a door/monster/treasure type of cave. I'd like to bring it some flavour. But, due to lack of time and inspiration... I don't have much ideas. I know I wanna put a big demon in disguise so that the girl Rachel see through it and banish the demon, which would lead to characters being even more intrigued by her. But I don't want her to overshadow player characters. So they should have things to do as magi and ressourceful companions.
I briefly considered a cave system with regio from the 4 realms, each with its own challenge, but I though that might be cliché, and why the hell 4 different regio would coexist like this in a cave system?
So, if you have any interesting idea, I'd be very interested in it