The main characters of the series are Ratchet and Clank. Ratchet is a lombax, a type of alien made up for the game. Clank is his robot friend. They travel in space ships through the universe on many adventures. In each game, Ratchet and Clank must work together to fight evil or bring cruel rulers to justice. The series is noted for using unique and extreme weapons and devices. Because of the popularity, the developer Insomniac Games added this feature to its other video games.