It was revealed unofficially through the Kombat Pack that Liu Kang will return in Mortal Kombat X. There is now a russian trailer that has now shown Mortal Kombat and some more details on the story:
Looks like Mr. Kang has been possessed after the events following Mortal Kombat 9; perhaps returning as the undead Liu Kang. The trailer also shows a bit more information about Kung Lao; stating that his soul was also taken over by evil alongside Liu Kang. Other characters are given a better look at, and added speculated characters are shown. Kung Lao’s descendent bow and arrow user Kung Jin confronting the grizzly and battle worn Sub Zero; and Bo Rai Cho speaking to Raiden suggesting his possible inclusion in the roster.
The announcements are ramping up as the game’s release date comes closer. Mortal Kombat X will be out on April the 14th for your bone crushing, blood spewing needs.