As a Senator in the Old Republic, Palpatine was a seemingly unassuming man serving during a time of corruption, social injustice, and bureaucratic abuses. However, when Palpatine achieved leadership of the Galactic Senate, his true nature as a power-hungry tyrant became apparent as he introduced the New Order and declared himself Emperor. In time the Jedi were destroyed, the Senate was disbanded and he became the undisputed ruler of the most powerful empire the galaxy had ever seen. The Imperial Palace, built on Coruscant as the headquarters of the Emperor, is taller than any other structure on the planet including the neighboring Senate building and the imposing Jedi Temple. The Palace is said to be an impregnable fortress, with some areas decorated by Palpatine with patterns based on ancient Sith hieroglyphics."
Both strong in the dark side of the Force and possessed of a subtle and dangerous mind, Palpatine has a genius for manipulation. How the Emperor gained mastery of the dark side of the Force remains a mystery, but it was through his influence that Obi-Wan's apprentice later became the Dark Lord of the Sith, Darth Vader.
For a time, the Emperor believed that nothing could seriously threaten his rule: his old enemy, Mon Mothma, was clever and strong, and the Rebel Alliance was growing, but without the Force, neither could ever become a serious threat. In some ways, the Rebellion was a useful scapegoat, giving him an excuse to further undermine and corrupt the Old Republic's justice under the pretense of an emergency state of martial law. Soon he would not need them any more, and in the fullness of time, they would be attended to. All was right with the galaxy and the New Order was unstoppable.
But the Emperor has become aware of a new current in the ever-flowing energy of the Force. It began as a subtle, barely perceptible surge, but in a short time has grown into the bright light that he now knows as Luke Skywalker. Lord Vader observed to his Emperor that if Skywalker could be turned to the dark side of the Force, "he would become a powerful ally." And so the Emperor plots to deal with this young Skywalker: he will join the New Order, or he will die. Pitting Vader against Skywalker, with all their psychological threats for each other, is all part of the Emperor's plan, and he remains evilly confident that no matter who is killed, he will settle the balance of the Force to his satisfaction.