Recently the biggest trend in fighting games has been inter-company crossovers. Solid Snake and Sonic in Super Smash Bros Brawl, the triplet of Star Wars characters in Soul Calibur IV, and Spartan-458 in Dead or Alive 4 are all examples of fighting games that have guest characters that don't really mesh into the series. Of course, the whole idea could be traced back to Marvel vs. Capcom, where the superheroes of Marvel faced off with Capcom's greatest characters.
The latest in this rather odd line of crossovers, Mortal Kombat vs. DC Universe will pit Mortal Kombat characters against the heroes and villains from the DC comic books. But how will a series known for spine-ripping fatalities match up with a universe where the heroes refuse to kill?