Li Mei
Reptile
Sonya
Jax
Raiden

Sonya:

Becomes General and head of the whole SF team. According to her ending she handpicked a team and is in Earth doing some research or fighting other problems, while in Outworld, Kenshi has discovered more about the Red Dragon.

Reason why Kenshi is in the game, and Sonya has not been confirmed yet.

Jax:

Killed Hsu Hao in Outworld. Reason why we will ever see Hsu Hao (I guess). Maybe he never made it to earth, and its trapped in Outworld, reason why he is in the game.

Rayden:

Because he just tells a story.

Reptile:

OBVIOUS.

Nitara and Cyrax.

Nitara is in her realm, and Cyrax in earth, reason why we have not seen them yet.

Li Mei..raiden..and i got a question ..in one of the endings in DA ..i think quan chi's..im not sure ..didnt liu kangs soul go inside kano..so how would liu be a spirit or zombie??jus curious

Raiden...He actually mentions the return of the DK in his ending.

Reptile...Show the rebirth of the DK.

Li Mei.....She becomes a member of the DK army.