Q & As About 'Star Wars': How did Anakin Skywalker come up with the name Darth Vader?

The evil Lord Darth Vader, the Sith identity assumed by Anakin Skywalker after his fall to the Dark Side. © 1980 Lucasfilm Ltd. (LFL)
How did Anakin Skywalker come up with the name Darth Vader?
Actually, Anakin didn’t come up with his Sith persona’s nom de guerre; it was chosen for him by his new Master, Sheev Palpatine, Supreme Chancellor of the Galactic Republic and soon-to-be Emperor of the First Galactic Empire.
This bit of business occurs in Act III of Star Wars - Episode III: Revenge of the Sith after Palpatine, the recently-revealed Sith Lord, has killed three of the Jedi Order’s most experienced Masters in a one-sided clash of lightsabers in his Senate Office suite and manipulated a conflicted Anakin into helping him kill a fourth, senior Jedi Master Mace Windu.

MACE raises his sword to kill the CHANCELLOR.
ANAKIN: (continuing) He must live . . .
PALPATINE: Please don't, please don't . . .
ANAKIN: I need him . . .
PALPATINE: Please don't . . .
Just as MACE is about to slash PALPATINE, ANAKIN steps in and cuts off the Jedi's hand holding the lightsaber.
As MACE stares at ANAKIN in shock, PALPATINE springs to life.
The full force of Palpatine's powerful Bolts blasts MACE. He attempts to deflect them with his one good hand, but the force is too great. As blue rays engulf his body, he is flung out the window and falls twenty stories to his death. No more screams. No more moans. PALPATINE lowers his arm.
PALPATINE: Power! Unlimited power!
His face has changed into a horrible mask of evil. ANAKIN looks on in horror. PALPATINE cackles.
ANAKIN: What have I done?
ANAKIN sits.
PALPATINE: You are fulfilling your destiny, Anakin. Become my apprentice. Learn to use the dark side of the Force.
ANAKIN: I will do whatever you ask.
ANAKIN: Just help me save Padme's life. I can't live without her. I won't let her die. I want the power to stop death.
PALPATINE: To cheat death is a power only one has achieved, but if we work together, I know we can discover the secret.
ANAKIN kneels before PALPATINE.
ANAKIN: I pledge myself to your teachings. To the ways of the Sith.
PALPATINE: Good. Good. The Force is strong with you. A powerful Sith you will become. Henceforth, you shall be known as Darth . . . Vader.
ANAKIN: Thank you. my Master.
On the movie screen, Ian McDiarmid’s performance of the scene seems to imply, through body language cues, that he seemingly plucks the name “Darth Vader” out of the ether, rather than making it clear to the audience that he gave the matter much thought.