"San'Shyuum (Latin Perfidia vermis, meaning "Worms of Treachery"), also known as Prophets by humanity, are a species who were the leadership caste within the Covenant, and one of the more mysterious member races of the hierarchy. Prophets appear to exert complete control over religious and political affairs, thus fulfilling their role as leaders. The Prophets enforce a misguided theology based on the false belief that firing the Halo Array will start the Great Journey, transcending them into a god-like status." 
                                                                                                                                             From halo.fandom.com