I would love to join in this! Especially as a co-GM!

(inb4: don't bother with my postcount, I'm new here but NOT new to writing)
Although, I'm not 100% sure you and I would be on the same track, so I wanna ask a few questions:
I love mysteries and fiction but the stories often end up getting tied around a single, centralized player and then die.
Or they'll be too sandboxy. How do you plan on preventing that?

Magic? Guns? Magic guns? Neither and solely driven on character development?

Mysteries; Killer? Monster maker? Antagonist ideas other than a plot?

In short; plot ideas? I love worldbuilding and I'm fantastic at it if I do say so myself.

<3!