Guest mk characters. My vote would be Baraka, sub-zero, scorpion, kitana, sonya, raiden, liu kang. But I'm sure whatever or whoever they pick will be great guest characters. *cough* bo'rai'cho *cough* ;)
oh my god, oh my god, as a dc and comic book fan I'm going crazy, as an mk player already practicing Shazam combos in my brain for this beautiful game. :D