DC Universe Online is a subscription-based MMORPG set in the DC Universe. Players create custom heroes and choose a famed DC hero, such as Superman, or villain, such as Lex Luthor, to be their mentor. Players' choice of mentor affects their starting location and rewards. Players progress chiefly through player versus environment missions, though Player versus Player combat is possible. In some instanced missions, players are able to control iconic DC heroes and villains.