I was thinking lately about ideas for a sub-boss. i personally would like to see liu kang return as an evil sub boss, perhaps the dragon king would have captured his soul and is under the dragon king's controll.
When you get to him he'll be in a form of a mummified dragon soilder(dragon kings army), he could have all his moves,and would be very fast and after you defeat him he would become enraged and filled with fury, and as he gets angrier he's armor breaks, and he changes he's form in that of a dragon.
At this point round two begins, liu kang will be now slower but much stronger and be able to breath fire, but once you defeat him he changes once again to he's most dangerous and lethal form...a form of a ghost.
This is round 3 , liu kang will now be fast and strong, and would have supernatural powers( cant really think of any ones right now.)
And once you defeat him, he's soul will finnally find peace and would thank you and finally ascend to the heavens. What do you guys think, feel free to post your own ideas.