Arkham City had one of the greatest twists and one of the most terrifying reveals ever, and that was that Clayface masquerading around Arkham City as The Joker while Batman raced to find a cure for his ailing enemy. When Batman asks Clayface why he has allied himself with The Joker, Clayface responds by stating it was for the role of a lifetime! If Joker truly is dead, an easy way to incorporate him would be to have Clayface once again impersonate him. But why would Clayface want to impersonate Joker once again? Because, Basil Karlo (aka Clayface) was an actor who pretty much lost his mind when they remade one of his film classics. He was a vain and narcissistic performer who always took great pride in every role he inhabited. Admitting that he allied with Joker just to play "the role of a lifetime" could transition well into Arkham Knight where Clayface assumes Joker's identity because he feels he did better than the original. Hopefully the irony of Clayface playing a "rebooted" Joker is not lost on you, my dear readers.