Supernatural Chapter? Would you throw your money at the screen?
Think about it, they could make the Winchester brothers a survivor version of legion, so just one survivor for the chapter where the cosmetic appearance changes between either Sam or Dean like it does for Frank and Suzy on Legion. Perhaps like Ash, Sam and Dean could each have a couple lines of dialogue.
Dean: "Son of bitch!"
And then for the killer they could either go with Lucifer or Cowley maybe?
I would instantly buy this chapter the second it was available!