RU.08 said:
In the original trilogy, Darth Vader is never referred to as a Sith, he’s a Jedi that has been converted to the dark side (for example I’ve always understood “Your sad devotion to that ancient religion …” to be referring to him as a Jedi not Sith).
It is unfortunate, I think, that there is now so much convoluted garbage in the Star Wars franchise that modern fans don’t understand the original trilogy.
From the original 1976 script:
The awesome, seven-foot-tall Dark Lord of the SITH makes his way into the blinding light of the main passageway. This is Darth Vader, right hand of the Emperor.