Darth Vader is a radical left-wing Communist from Hell. The kind only CNN (the Communist News Network) could love. His ultimate goal in life is to destroy Truthiness, as evidenced in the Colbert-inspired Star Wars trilogies.
Darth Vader came into being after being defeated by his former mentor, Obi-Wan Kenobi, in his native Communist Russia and burned to death in a volcano. After being brought back to life by Darth Sidious (possibly Karl Rove in disguise), Vader went on a killing-spree, murdering all the Jedi and Conservatives he could find before finally being defeated at the White House by the Greatest President Ever.
Afterwards, Darth Vader created the Death Star to defeat George W. Bush but was defeated when Luke Skywalker-Colbert destroyed it, earning him the illustrious Tip of the Hat by Stephen Colbert himself.
Later, Darth Vader cut off Luke's right arm, trying to turn him into a leftie, but Luke refused the temptation.
Darth Vader was finally turned to the side of Truthiness by Skywalker-Colbert, just before he blew up the second Death Star, destroying Communism and all enemies of Truthiness.
Darth Vader is also the only known Jew Jedi (J.J.) in the galaxy. This is probably the reason he left the Jedi and joined the Dark Side; he was too cheap to pay for a lightsaber that was five dollars more, so he turned his back on all Jedi.