Yeah, I know there's another thread for guest characters, but it's about suggesting which non-MK characters should appear in future games. This thread is about something else entirely.

I was thinking that there could be a way to incorporate guest characters in the story mode, if both guests and the story mode made an appearance in MK10 or beyond. They could make cameos as undead opponents in the netherrealm.

If players ever found themselves fighting many undead, nameless minions of Quan Chi, rather than named characters such as the deceased heroes in MK9, then guest characters (if there are any) could randomly appear as opponents. They would have no dialogue, no meaningful interaction with your character(s), their cameos would largely be gameplay ones. They may appear in cutscenes before the fight, with Quan Chi ordering them to kill whoever you're playing as, but that's it.

The same thing could be done with DLC characters (once you've bought them) or any playable but non-canon characters. Who you'd fight in those segments would alternate between nameless foes, guests (if there are any), DLCs and non-canon MK characters already available/unlockable (MK2 Jax in MKT would count as one, for example).