My thoughts/suggestion would be something like a haunted castle, have something like vampires, ghosts, and somewhat medieval theme.
Also, i would like to ask, are you the artist for all of that ? it's well drawn and written.
Yeah, something like that is certainly possible but I am unsure when it would be implemented.
I am the sole dev of this game so I handle everything within it including the art/writing/programming/etc. Thanks!