Like the Charles Exavier wheel chair cameo from this episode, and how classroom sequence showed David's father as a bald psychic, and Lenny says she knows David's real father. But I doubt we'll ever see Charles Exavier on the show or any of the main mutants. I'll be really interested to see how they wrap the season or even show up, because if David is ever in a position where is has full control over his powers without the fear of the Shadow King then the show has to be over, because that's just how powerful he is.