As a young tree Tyrone was assigned one task- to assassinate the leader of the order of robotics (The Master) and he succeeded. In fact do to his actions the entire leadership of the order fell, and so he eventually became the next Pulpatine. Now as the leader of the tree empire he conspires to do the same as the order of robotics once tried, to unite the world under his rule.
Pulpatine for a while traveled with "The Muppets" until his vessel was destroyed. Then he left shortly after threatening the king (It was at this point that he became a npc) and eventually joined the "Super Happy Fun Group" under his previous name Tyrone. Eventually he was revealed as Pulpatine to Prototype, and so ended up leaving the player character party altogether.