So MKX is confirmed to be the sequel to Mortal Kombat And take place from the ending and 25 years following. It will also have returning characters from the story who may or may not be playable but might give us insight on who we can expect to see.
I replayed mk9 recently to jog my memory of who actually is and isn't dead.
DEAD:
Kung Lao
Kabal
Jax
Smoke
Jade
Kitana
Sub/cyber sub zero
Stryker
Nightwolf
Liu Kang
Sindel
Shang Tsung
Unknown/ presumed dead:
Noob Saibot
Still living:
Quan Chi
Raiden
Sonya Blade
Johnny Cage
Ermac
Reptile
Mileena
Cyrax
Sektor
Kano
Baraka
Sheeva
Note that I made this list by which characters we actually see die or in zombie form in the NetherRealm for Raiden to fight to confirm death. I made a second list of characters who did not die or it was unclear what happened to them. Also just because they are survivors of the mk9 story doesn't mean I think they will return. Only that we can rule out the ones we watched die
I'm bored so over-analysis time.
Dead:
Kung lao- probably won't return, however his playstyle and storyline is so iconic to the series that I wouldn't be surprised if we see a spiritual successor, either in the form of offspring or someone from the same group.
Kabal- From a very personal standpoint, I hope to god he stays dead. Objectively, it doesn't make too much sesne to bring him back as his purpose in the plot is resolved, and he doesn't carry much reason for them to jump through hoops.
Jax- Part of the Sonya/Cage thing which I 'll get to later, but in short I doubt he's coming back. Their entire storyline seems wrapped up, so resurrecting him would be pointless.
Smoke- I doubt it, but I want it? I don't think robo anything will be in this game, least of all smoke, but his single player ending had some potential. Still not likely.
Jade- Nope. Dead and plot pointless.
Kitana- maybe, but leaning towards nope. She's iconic and what not, so maybe a spiritual successor, but I highly doubt kitana herself will show, especially with mileena alive.
Sub/cyber sub- this brings up a good question. Who the fuck is the current MK9 sub zero? From my understanding, he shouldn't even exist....so...yeah(and clearly scorpion thinks he's the original, but the guy isn't exactly renowned for his thoroughness with genealogy)? Anyways his existence as a human strikes me as a major sign we won't be getting robots.
Stryker- Nope. Fills a very small roll and cassie's already got guns. Maybe we'll get another "cop thrown into this" guy, but I doubt it's stryker.
Nightwolf- maybe in some altered form. This has more to do with sindel, but essentially due to how his death occurred, there's a small chance, and he does fill a Raiden like roll in the plot. That said I wouldn't bet on it.
Liu Kang- maybe. Mostly the same as kung lao(spiritual successor), but given his singleplayer ending there's a chance of him making it in as something else entirely.
Sindel- maybe. I read somewhere she was confirmed(no source though so meh), and the only real reason I could see it was they made such a big deal about her being a complete badass in MK9, and her death was a little less certain than others.
Shang- Doubt it. As much as I'd love to see what they do with him this time, his chances of returning seem very slim, especially if they want to get away from the old plot and establish something new finally.
Noob- maybe he's sub zero(but then he wouldn't claim to be innocent?)....i dunno. I doubt it, but sub's existence gives him a small chance.
Living-
Quan chi- it makes a lot of sense given everything we know already, so i'd say he's one of the most likely on this list.
Raiden- Possibly. In the plot, probably, playable fighter....not so sure.
Sonya/johnny- almost assuredly no. Cassie fills their legacy, and while not being them, there's a rather interesting issue of having a daughter kneecap mommy before blowing her brains out, or daddy ripping his daughters torso off. I know that technically you could say that's happened in the game before, but I think this would be pushing boundries they don't need to, and would make little plot sense. They might be in the plot, but I doubt they're playable.
Ermac- seems all but confirmed. Concept art + character select gives him good odds, which is interesting because the guy is kinda shallow when it comes to plot motivation, especially with everyone dead. Maybe he'll finally play a larger role in things? He's my main since he UMK3, but god knows I wouldn't have given him good odds if you just told me about the plot of X.
Reptile- maybe. He plays a very small role usually, and that doesn't help his chances, and I think insect lady sorta fills the "human but also something else" niche he used to have. Still he's one of the more original characters, not just in legacy, but in playstyle, and that could help.
Mileena- maybe. The biggest thing she has going for her is "not dead female ninja". I have no doubt they'd be willing to just axe the entire concept, but if they want to keep it around it's a lot easier to reintroduce melieena than to somehow jump through hoops to get kitana/jade back. I do think there will be at least one "female ninja" character who somehow brings back their styles(maybe one who can switch between the mileena/kitana/jade styles? Not sure how to make that work plot wise, but it from a design standpoint it seems like a no brainer)
Cyrax/sektor- unlikely. Sektor is already hurt in that it seems Cassie has some similar moves(lock on/positional missiles), but mostly I think they're trying to avoid the "robot ninja's" entirely. It's a shame because I really did like both of them, but I can see how they may not mesh with the direction they want MK X to go, so I don't think we'll see either one of them coming back.
Kano- probably not. With johnnny/sonya likely out of the picture, it seems silly to bring back kano, but he is an original cast member, and he could serve as plot motivation for cassie.
Baraka- Likely no. he doesn't serve enough of a purpose in the plot really, so it'd be easy to cut him, especially if they're trying to find room for new faces.
Sheeva- same as Baraka.