Darth Vader was the sith name given to Anakin Skywalker when he joined Palpatine better known as Sidious a sith lord. As Darth Vader, Anakin was evil cold and had no mercy, after his battle with Jedi Master Obi wan Kenobi on Mustafar. Vader was badly injured and burned losing some of his limbs. To survive, he was placed in a special life support suit to keep him alive. Vader would then serve the dark side through his evil master Sidious and keep his master's control of the galaxy.
In the last moments of his life, he was rescued from the darkness by his son Luke and went on to kill his dark master Sidious and save Luke. He then became Anakin Skywalker again and became one with the force.