Being a superhero is cool. Being a supervillain is cooler. At least that's the premise behind NCSoft's upcoming City of Villains, a quasi-expansion/standalone that can work together with the existing City of Heroes, or not, depending on whether you happen to own City of Heroes as well. It's kinda hard to describe, since I've never really seen a situation quite like this before. City of Villains will not require that you own City of Heroes to play, but some interactions between the two games will not be available. Likewise, if you own City of Heroes and do not get City of Villains, there will be some interactions with the villains which you won't get to do, along with some City of Villains features (such as base-building) that won't be available. Having both titles together is your best bet to get the most out of either, but pricing for having an account in both games is still up in the air.