Maetel's mother, and ruler of the mechanized empire. Once a gentle woman, Prometheum created the machine empire believing it would be good for humanity. Prometheum has considerably difference physical characteristics in each of her appearances, appearing as a humanoid in the television series and movie, and a two-faced head in the manga. Prometheum is destroyed with the destruction of Andromeda in the manga and television series, and killed by Claire in the movie version. Her spirit occupies the planet Great Andromeda in Adieu Galaxy Express 999 but perishes when that planet is destroyed by Siren the Witch.