The Rulers of the Universe were a group of elite individuals who control every phenomena or events in the universe through their computers in a ship. Examples of these events were natural disasters such as hurricanes or earthquakes, or economic and political events such as rise and fall of governments. (AUDIO: I Went to a Marvellous Party) During the early days of the Time War, the Rulers of the Universe asked for the help of the Eighth Doctor to let them participate in the said battle.
River Song destroyed the organization by destroying their ship to disable them from controlling the universe. (AUDIO: The Rulers of the Universe)