>>531736896
The main boss becomes the schizoboss when certain requirements are met. This would be Asgore in Chapter 5's case, but I'm not sure if Toby would give the superboss treatment to a character who was already the neutral route's penultimate fight in Undertale. But I do think this idea would work well as a sendoff to the Shadow Crystal bosses, giving the schizo such an important role, since the Chapter 5 one will be the last. I don't know how you'd get Asgore to this point, maybe you get Friend to manipulate him or something.