City of Villains is a standalone expansion to the popular MMORPG City of Heroes, designed for Mac users. It introduces five new character archetypes exclusive to villain characters, expanding the gameplay options significantly. Players can explore new maps and engage in Player vs. Player (PvP) combat in newly introduced PvP Zones, enhancing the competitive aspect of the game. This expansion is accessible with the same subscription fee as City of Heroes, making it an attractive option for those looking to dive into villainous gameplay.

The retail box of City of Villains includes four CD-ROMs for installation, featuring content current to Issue 6, along with a limited edition HeroClix figure of one of the game's villains and a detailed poster map of the Rogue Isles. A serial code is provided for game access and includes one month of gameplay. Following the acquisition by NCSoft in 2008, players who own either title can access both games without additional costs, making it a valuable addition to any RPG enthusiast's library.