IS THE SECRET REVEALED?

I just received this new and tantalizing illustration from my artistic fan, A.L., who writes:  

Well...I yet again want to introduce another of my dedicated fan works to you and the world to see!  This picture is only about the 3rd book “This Book Is Not Good For You” and in reality, it’s 4 ½ by 4 ½ inches big!  On my last picture, many people had complained about many things being inaccurate about it and I would reply “That’s what it is supposed to be.  If it were accurate, then Midnight Sun would have kidnapped me by now!  They wouldn’t want their secrets so perfectly portrayed to the public!”—but of course, I can’t.  Also, I’ve changed some of the character designs from before if anyone notices...  

Thank you, A.L.!  I only you hope YOU haven't revealed anymore secrets this time...