In all technicality, Darth Vader is stronger. The Skywalker bloodline is, according to the original storyline, the strongest line of force users. According to the movies, Vader was actually stronger than the Emperor. But he was still under Palpatine's control, due to the Emperor instilling fear into Vader. Darth Revan was a very powerful Sith Lord, the strongest in his time (before Darth Bane), But even he didn't have the same level of power Darth Vader had.
In terms of raw power and abilities, Darth Reven is considered to be stronger than Darth Vader. Darth Reven was a highly skilled and powerful Sith Lord, known for his mastery of the Force and lightsaber combat. However, Vader's combat experience and ruthless determination could make him a formidable opponent in a showdown.
Darth Vader
If it the force was real than Darth Vader definitely.
No, Darth Vader is stronger in the force and could beat Starkiller easily, if he didn't have that suit on.
The Emperor is the stronger of the two because he taught Darth Vader everythinghe knows, and he can shoot lightning from his fingers.Mr.Seidschlag
yes starkiller proved stronger then Darth Vader in both the force unleashed 1 and force unleashed 2.
Darth Vader
Darth Vader
Definitely Darth Vader
Darth Vader
none because they are the same person
Definitely Darth Vader
Darth Vader IS a Sith Lord hence why he is sometimes called 'Lord Vader'. Whether another Sith Lord is stronger than him is completely debatable.