A player character may sometimes be based on a real person, such as in sports games that use the names and looks of real sports people. Historical people and leaders may sometimes appear as characters too, such as in strategy or empire building games like Sid Meier's "Civilization" series. These characters are avatars rather than true player characters, because the player character's name and image have little or even no effect on the game itself. Avatars are also often seen in casino game simulations.