Here I am, always with questions... But this one is just out of curiosity for castmates in terms of how they may interact with an AU!

If a character is already in the game and someone apps a castmate, how would the mods envision those two AUs to line up, generally speaking? I know a fair amount of that is up to player discretion, but mostly my point here is how you'd expect the character already in the game to integrate a castmate into an AU, if at all! I can give a more specific example if needed, but I was keeping this as general as possible since I feel like other people might have this question in the future, haha