Heroes of Gaia is a free to play, Flash-based fantasy MMO game. Players choose from one of four races, Humans, Elves, Orcs, or Undead. Using a time and production-based game mechanic, players build castles, which allow them to train armies of many different types of soldiers, recruit Heroes, and partake in both PvE (Player vs Environment) and PvP (Player vs Player) combat in order to dominate the land. Heroes of Gaia also has a Guild system where players are able to forge alliances and declare wars on other guilds.