So I've actually had this idea for a long time, but I've had no clue how to go about it. Really, it wasn't even a roleplay idea, but just more of a concept that popped into my head more than a year ago. 

Imagine: a shadow creature (a silhouette, really) who lives completely undefined because it LIVES in shadow. So at that point, it has no autonomy.

Then, light enters the world. Something completely separate, creating a clear barrier between the undefined darkness, and what gives the silhouette a sense of self and shape. Imagine a shadow navigating a new, defined, three-dimensional world as a 2D shape while trying to figure out exactly why it exists. Think of almost like Peter Pan's shadow, but not really.

Once again, I still have no clue if this would be a cool idea or not, but I thought it was interesting.