The Forgotten River

Yeah. The name is lame, I know. Read the url.

First reported by Grand Wizard Philonious of the Blue Wastes, the Forgotten River is generally misconstrued as a thought experiment or a philosophical way of representing memory loss. Most tomes refer to it as such, a simple way of understanding what happens to the brain when memories are magically removed from a subjects brain.

The truth was discovered (or at least recently rediscovered) when Philonious decided to read the mind of his victims as he destroyed their minds. When removing their memories, Philonious saw a grey river full of debris crashing through their thoughts, sweeping their most personal moments away. Curiously, the river did not appear when removing memories of public places or things, only cherished secrets of the individual.

Thinking it was perhaps a quirk of his method, Philonious studied an entirely new way to scour memories from minds. Even with his new dweomer, Philonious still saw the river in the minds of people who lost memories only they remembered. The river itself was recorded as being, "filled to the brim with archetecture ancient and strange, trinkets and people unrecognizable," in his published paper on the subject.

The last thing Philonious wrote was that he was intending to send an expedition down the mental torrent to explore wherever the stream took him.

I feel like in the past I've failed to have locations of significance in the worlds I've built, but I think this could be an interesting way to give the metaphysics of a world an interesting location. Not just a plane on the Great Wheel that hundreds of writers talk about and thousands of players encounter, but something unique and special which gives wonder and awe to anyone I DM for. I have a few ideas for how it could be used:

The villain is committing genocide against people across the multiverse, but where they are at any point is hard to pin down. By examining the river one may be able to recognize the archetecture of the memories which are lost forever, hence learning the location of the BBEG. Something similar could be done with a monster of person who eats and destroys thoughts and memories.

An ancient and forgotten relic must be found in order to save the world, but there is no recorded history of it anymore, and anyone who knew about it is long dead. You could search desperately through hundreds of ruins of civilizations, or risk travelling down the river to wherever it ends. (Note, I want to write about this eventually. Uncle David's game had an interpretation of the land of forgotten secrets, but I think that exploring that idea and it's ramifications could lead to some really cool and interesting destinations)

If everyone forgets about the river, it could swallow itself. What does that mean? Is that possible? Do you care? Idk, the idea of a river flowing into itself infinitely seemed interesting to me.

But seriously if you have a better name tell me because I hate this one.