All of the following is borrowed from Emperor Sub Zeros Site. ( I cant do a direct link b/c he has scanned photos ) But here are HIS predictions of retunring characters..i thought it to be interesting.

Possible Returning Characters:

Kung Lao ( 85% probability)- We all know Kung Lao has taken the job of the hero, and he did a damn good job in MKDA. Kung Lao more than likely killed Shang Tsung, and will most likely be the hero again in MKD. The 15% chance that he will not be in the game is considered because he may have gone back to a life of peace, which he did for a short while after MK3.

Johnny Cage ( 50% probability)- Johnny Cage is one of those “love him or hate him” MK characters. Since Boon has decided to give many fans what they want, Johnny Cage is 50/50.

Mavado ( 75% probability)- After his ending in MKDA, Mavado is told to look out for the Ling Kuei, which could defiantly call for another fun MK clan war (woo hoo) Also it appears that the Special Forces, and the one special blind man who never gives up are still searching for this honorable Red Dragon member.

Jax & Sonya ( 50% probability)- During the interview with Ed Boon in the PSM magazine, he said they will introduce a lot of old characters that have not been in a lot of MK games, and a lot of new. Some other classic MK characters will also be released. I am still not sure of the Special Forces. We’ll have to wait and see.

Sareena ( 80% probability)- After her endings in MKTE, it’s almost certain something will occur between her and Sub-Zero in the near future. It is hinted that she betrayed him, and possibly killed him.

Frost ( 20% probability)- After her ending in MKDA, it’s highly unlikely that we will be seeing her in MKD. Although, anything can happen in the MK world, and she can always fight on the side of evil.

Raiden ( 90% probability)- Being in almost every MK game its almost likely Raiden will be in this one to guide and help out the chosen ones. Raiden could also not be in the game, and we could see someone take his place, perhaps Fujin, or Ashrah?

Quan Ch ( 60% probability)- A component of the Deadly Alliance, Quan Chi, is rumoured dead after the Deadly Alliance. Ed Boon in the magazine scan stated that we would "see what happened to the Deadly Alliance", possibly implying that the alliance is severed.

Shang Tsung ( 80% probability)- A component of the Deadly Alliance, Shang Tsung, is rumoured dead after the Deadly Alliance. Ed Boon in the magazine scan stated that we would "see what happened to the Deadly Alliance", possibly implying that the alliance is severed.

Kitana ( 90% probability)- It is more than likely the Princess of Edenia will return, mostly because her mother and Queen is back, and so is her evil clone Mileena. Kitana will probably be set out to once again, destroy her clone, and help her mother.

Dairou ( 50% probability)- With many sketches of him in MKDA, Dairou was originally supposed to be in the game. With lack of time, the team could not fit him in. If you unlock his concept art in the krypt in MDKA, it hints that he is a possibility on the next installment.

Sektor/Cyrax ( 70% probability)-
After seeing Sektor’s ending in MKTE, it could possibly be predicted that he will return and wage war with his new clan. Also Cyrax is likely to return with the Special Forces to help them with the OWIA. Sektor's clan, the Tekunin, will likely be a prominent power.

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Notice How he Doesnt even Mention Li Mei, and gave Frost a 20 % chance? Frost was Cool ( no pun intended ) and i'd like her back.