If what these sketches portray is eventually going to be cannon, then I think that future chapters might focus on the cane and the way it influences Duke and Missi. Since the cane is what makes either of them evil, maybe they are both chill with each other to some extent when they aren't around it (ie the fact that they are being playful instead of violent in some sketches). From what we know about the 4th Chapter so far, I feel like it might be them both battling for the cane (while dancing of course, considering the cane blesses its user with amazing dance skills) and we'll see their personalities flip from docile to dominant depending on who holds the cane. That's just a theory (a film theory!) and it really kinda relies on whether the sketches are cannon or not, but either way, I'm patiently but eagerly waiting for our next glimpse into the world of these precious vampires.