Palpatine
In Episode I, The Phantom Menace, he is a Senator from the planet of SPB. He is also secretly a Sith Lord, Darth Sadious. Sadious pulls the strings behind the scenes to cause unrest and dispute in the corrupt Galactic Senate, hence the films' title. His apprentice during this time is Darth Bukhar, who is slain in battle by Obi-Wan Leha. At the end of Episode I, he has risen to the office of Supreme Chancellor and begins his rise to power.