So far there are four
If you’re picking up Mortal Kombat X but don’t feel like shelling out for the DLC, I don’t blame you. The good news is that according to an interview with Angry Joe, Ed Boon has confirmed that all four current DLC characters (Tanya, Predator, Jason, Tremor) will be playable in some limited form for free. As a feature within the Tower Mode, there will be three towers that allow players to “try” the DLC. Characters will shift in and out based on a rotation, but they won’t be able to be used in ranked play — they’re strictly for testing.
While day-one DLC isn’t ideal, a ton of fighting games already do it and don’t add this option. By letting people get to know all four add-on characters they at least allow players to stay competitive and learn the ins and outs, frames, and movesets of said fighters.
AngryJoe Mortal Kombat X Interview w/ Ed Boon [YouTube]