Darth Vader (Legends)

Darth Vader is one of the main antagonists of Star Wars IV,V, and VI. Once the Jedi knight Anakin Skywalker Anakin fell under the evil influence of Chancellor Palpatine aka Darth Sidious. He slaughtered Jedi to help with the rise of Sidious and eventually Sidious was made Galactic Emperor. Though loyal to the Emperor his own son Luke Skywalker persuaded him to turn back to the light side of the force and he killed the Emperor killing himself in the process