Each game varies somewhat from the tradition it is derived from; for example, Baba Yaga, a character borrowed from Slavic folklore, appears in the first game which is based on German mythology. The second game, which uses Middle Eastern folklore, introduces several Arab and African-themed characters who reappear in the third game based on Egyptian mythology. Characters from every game and genre in the series reappear in the fourth and fifth games. In addition to deviating from the player's expectations of the culture represented in each game, the series also includes a number of intentional anachronisms, such as the pizza-loving mad scientists in the later games.