This is Darth Sidious. Before he turned to the dark side he was known as Chancellor Palpatine. As you can tell his face isn’t very normal, this is because a Jedi called Mace Windu deflected Chancelor palpatine’s electric rays with his Light Saber making Palpatine’s face get burned and deformed. He then sought out to kill all the Jedi’s of the galaxy. He also made a few Jedi’s turn to the dark side like Anakin Skywalker who he saved when his legs were cut off by his mentor who was sensing the dark side in Anakin. this meant that Obi Wan Kenobi (Anakin’s mentor) knew that he was going to turn to the dark side so he tried to eliminate him before he turned to a Sith (a Jedi that is part of the dark side).