When the Jedi Anakin Skywalker swore loyalty to Darth Sidious in order to gain the power of the dark side of the Force, he became Darth Vader. He is perhaps the most feared being in the galaxy, as the Emperor himself likes to keep a low profile.
Palpatine was a chancellor of the Old Republic -- and dedicated to its total overthrow. Secretly, as Darth Sidious, he eradicated the Jedi Order and then declared himself Emperor.
Luke’s outfit from his adventures on Endor. In it he rescued Han from Jabba, faced the Emperor, and turned his father from the Dark Side.
Jedi Knight Obi-Wan served as a General in the Clone Wars, where he guided young Anakin Skywalker. Following the rise of Darth Vader, he hid on Tatooine, keeping a watchful eye over Anakin's son Luke Skywalker.
One of the greatest Jedi Masters, wise even beyond his 900 years, and skilled with a lightsaber, Yoda is. Trained many Jedi, he has. Later into hiding on Dagobah he went, until arrived Luke Skywalker did. Syntax his strong point is not.