Darth Bane is obviously more powerful. He obtained almost all Sith-Holocrons and created the "Rule of Two". Besides, Darth Bane started as a Sith and died a Sith. Krayt started as a Jedi.
Many people think Darth Revan was an ultimate Sith, far more superior than Bane or Vader. They are wrong. Bane is one of the few true Sith. Darth Revan quit the Sith and helped the Jedi defeat his own Sith Empire. Darth Vader attempted to kill his master, a Sith master, Darth Sidious, to save his son, Luke skywalker, a Jedi Padawn. No Sith would sacrifice a Sith Master for a Jedi Padawan. Darth Krayt, of course, was one of the greatest sith. He was able to manipulate and control Darth Talon, the Darth Wyyrlok's, Darth Stryfe, and very, very briefly Cade Skywalker. Krayt also controled more Sith and one of the largest Sith Empires ever. He was seemingly unstoppable at the time. Darth Wyyrlok was also a great Sith, Evan though he didn't have his own empire. His daughter and grand daughter were also Darth Wyyrlok at some time. Darth Talon was also a very powerful Sith. Quinlan Voss would've been a great sith if Mace Windu hadn't tricked him.
Palpatine is the greatest sith in Star Wars history. He is also the most powerful. Incorrect, Darth Vader Killed Emperor Palpatine.So, Darth Vader Is. Darth Revan or Darth Nihlus more likely, and don't forget Exar Kun and Darth Bane - and Darth Vader turns back to a Jedi before he kills Palpatine, so as a Sith he was never more powerful than his master ( He's more machine now than man; twisted and evil, kept alive by his own dark will - Obi-Wan to Luke about Darth Vader in Return of the Jedi)
Darth Bane was the Dark Lord of the Sith who instigated the Rule of Two. He took a young girl, Zannah (whom he found on Ruusan) as his apprentice. He eventually formed a society that followed the Rule. For more info try http://www.starwars.wikia.org
Darth vader or count dooku dark bane darth sidious asaj ventress and many more sith
Mentioned in the movies: Darth Plagueis Darth Sidious (Senator/Chancellor Palpatine) Darth Maul Darth Tyranus (Count Dooku) Darth Vader (Anakin Skywalker) In the Expanded Universe (comics, novels, games, etc.), there are dozens more, e.g. Darth Bane, Mara Jade, Asajj Ventress, Darth Talon, Darth Sion, Darth Malak, Darth Revan, etc.
Revan however, defeated the Mandolorians, Mandolore the Ultimate himself, many Jedi masters and powerful Sith, discovered nearly eternal life, was able to hide his Sith legacy from all for nearly 3 millennia and was the Dark Lord of the Sith. So Revan is by far more powerful.
Yoda would defeat Darth Vador in a battle because he is much faster and more powerful. Darth Vador is slow.
"Tell me what you regard as your greatest strength, so I will know how best to undermine you; tell me of your greatest fear, so I will know which I must force you to face; tell me what you cherish most, so I will know what to take from you; and tell me what you crave, so that I might deny you."―Darth Plagueis"When your power eclipses mine I will become expendable. This is the Rule of Two: one Master and one apprentice. When you are ready to claim the mantle of Dark Lord as your own, you must do so by eliminating me."―Darth Bane to Darth Zannah"Two there should be; no more, no less. One to embody power, the other to crave it."―Darth Bane"Everything is proceeding as I have foreseen."―Darth Sidious"Know the power of the DarkSide."-Darth Sidious to Anakin Skywalker, not yet Lord Vader"Darkness calls to darkness. It calls to you. You can feel it like a heart beating within this temple."―Darth TalonDarth_Bane:_Path_of_Destruction
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.
Obi-Wan states to Darth Vader, "If you strike me down, I shall become more powerful than you can possibly imagine."
jango fett is not a verry powerful bounty hunter infact he is rated fifth place out of all star wars bounty hunters seen on star wars Darth maul is ranked fourth place out of all sith masters seen in star wars in the end i think Darth maul is more powerful there for Darth maul would win in a battle against jango fett
Darth Vader