I think Palpatine
If you're referring to Darth Sidious, his real name is Palpatine
Khameir Sarin
If you watch the 3rd episode of Star Wars, you will find out Anikin Skywalker turned into Darth Vader. Darth Vader and Anikin Skywalker are the same people.
Darth Plagueis' master's name was the Sith Lord Darth Tenebrous.
Darth Tyranus's master was not Darth Caedus. Caedus was way after Dooku had died. Darth Tyranus's real master was actually Darth Sidious (Chancellor Palpatine)
If it the force was real than Darth Vader definitely.
I can't name them all because that is a hard question my young padawan... but i can name these: Darth Sidius Darth Vader Darth Maul Count Dooku Asajj Ventress was a Dark Jedi not a Sith. Ignore this answer. Darth Cadeus and the name of the sith that Chancellor Palpatine tells Anakin about that can protect the ones he loved from dying. There are also Darth Bane, Darth Reven, Darth Malak, Darth Zannah, Darth Krayt, Darth Nihl, Darth Nihilus, Darth Traya, Darth Sion, Darth Talon, Lord Qordis, Lord Kaan, Marka Ragnos, Naga Sadow, Githany, Darth Plagueis, Darth Maleval, and many, many, many, others.
He didnt change it. Darth Sidious did when Anakin became a Sith. It is traditional for the Sith to bear the name "Darth."
There is much speculation as to Darth Maul's real name but common consensus seems to hold that his birth name was either Khameir Sarin or Manuel Gonzalez . Most sources lean toward the former .
Darth Vader's boyhood name was Ani.
Darth Maul is a Zabrak from Idronia.
Darth Vader and Benjamin Franklin were both famous but oddly enough Darth Vader is considered to be more famous when he wasn't even a real person!