LOL, I've already talked about this plenty of times, but heres an entry which covers Palpatine particularly-
" No one is quite sure how Palpatine was first introduced to the power of the dark side. He is the most powerful practitioner of the Sith ways in modern times. He studied the ancient ruins on the Sith mausoleum world of Korriban. He unlocked secrets of the Force from a captured Jedi Holocron. The dark side energies flowing through Palpatine's body were so intense, that they ravaged his mortal frame. The very source of Palpatine's strength was killing him.
To counter the dark side's consumption, Palpatine turned to a bizarre combination of technology and Sith magic. Palpatine used Spaarti cloning cylinders to create a store of younger bodies, and employed an ancient Sith technique to transfer his consciousness into a waiting clone. Thus, Palpatine could avoid death indefinitely -- as long as his supply of clones remained intact. He would change his form again and again, prolonging his life. Palpatine constructed a secret throne-world deep within the galaxy's core, on a shadowy world called Byss. Here, he kept his clones safe, protected by a loyal cadre of Dark Side Adepts.
Although Palpatine called for the extermination of the Jedi and any Force-sensitives who could conceivably challenge him, he did keep a few loyal agents who were trained in the Force. Darth Vader was chief among them, as his primary lieutenant and Sith apprentice. Palpatine also had a string of loyal, deadly agents referred to as his "Hands." Mara Jade was foremost among these dedicated enforcers.
At the Battle of Endor, Palpatine found himself facing death yet again. Betrayed by Vader, Palpatine's body was destroyed aboard the second Death Star. Separated from his clones, Palpatine was forced to survive in the maddening, bodiless existence of the void. Through sheer will he retained his identity, crossing the gulf of space to again take residence in his clone body. He barely survived Darth Vader's treachery. Palpatine remained sequestered at Byss while he rebuilt his strength, and his Empire.
Palpatine's rule was so absolute that his apparent death at Endor fragmented the Empire. With no obvious heir, opportunistic moffs and warlords set out to carve their own private fiefdoms where they could. Years of infighting worked to the advantage of the fledgling New Republic, who proceeded to reclaim three-fourths of the galaxy. One warlord who succeeded where imitators failed was Grand Admiral Thrawn, the only non-human to hold that rank. His cunning tactics and unerring strategies brought the Empire to the brink of victory five years after the Battle of Endor. Only a last minute betrayal spelled his defeat.
Spurred on by Thrawn's victories, the remaining Inner Circle of Imperial warlords staged a devastating attack on Coruscant. Whereas Thrawn sought to take the capital world intact, these Imperials attacked without compunction. Much of Imperial City was laid waste by the fighting, and the New Republic was forced to evacuate. Once on the surface, the Imperials splintered yet again, and skirmishes dragged on in amongst the ruined skyscrapers.
It was then that the resurrected Palpatine struck. Using his dark powers to invoke a Force storm of great magnitude, Palpatine swept Jedi Master Luke Skywalker to Byss. There, he revealed himself to Skywalker, and unveiled the true strength of the dark side. Faced with an immortal enemy, Skywalker did the unthinkable -- in order to defeat the dark side from within, Skywalker knelt before Palpatine, and declared himself his new apprentice. In these dark times, it seemed the Emperor had finally won.
Skywalker was too enmeshed in darkness to successfully rebel against his master. Although he sabotaged some of Palpatine's military ventures -- namely those involving immense war factories called World Devastators -- he still could do not draw himself from the pall of the dark side. It was only his sister, Leia Organa Solo, that gave him the extra strength he needed. With her presence, the two Skywalker twins were able to temporarily repulse Palpatine.
Unabated, the Emperor continued his scourge. Armed with an incredible new superweapon, the Galaxy Gun, Palpatine forced numerous New Republic worlds to capitulate to Imperial rule. Despite his growing Empire, Palpatine was again growing frail. His clones were failing him. He needed new blood. Palpatine targeted Leia's newborn son, Anakin Solo, as the next receptacle for his dark spirit. During an attempt to possess the child, Han Solo shot the ailing Palpatine in the back. Before his soul could enter Anakin's body, Palpatine was intercepted by a newfound Jedi, Empatojayos Brand. Cut off from a host body, Palpatine's essence dissipated, to be consumed by the madness that is the dark side. After so many years of bloodshed, the Emperor was truly dead."