I'm unsure if Emperor Malgus is more powerful than Vader or not. His boss fight is pretty impressive given the implication of him holding back, and his ability to choke three members of the team whilst lightsaber dueling one of them.
According to wookiee there is apparently some kind of canonical description of the fight in Annihilation but after browsing through I couldn't find it, so someone either made that up, got the source wrong, or I missed it. If the description exists, however, then Malgus is looking mighty powerful indeed.
Cornered in his throne room, Malgus activated the station's self-destruct sequence to destroy the fleets assaulting it before dueling the strike team sent to face him. But for all that he was a brutal and skilled fighter, Malgus' resolve weakened as the battle went on. Taking advantage of this, his attackers were able to use pulse grenades, Force powers and other means to force him over the edge of the platform and down the reactor shaft to his death.Their citation- The Old Republic: Annihilation
1.Darth Nox
Looze. Dark council level. ANd maztery of the ligthning, at thiz point that'z not over zelling Vader weaknezzez.... Unlike Malguz or Dooku... And I doubt than Vader can block thiz with hiz light zaber.....
Emperor wrath.
Win I guezz....
3.Ulic Qel-Droma
4.Count Dooku
5.Darth Malgus
6.Darth Bane (Even if he have really deadly ligthning... Vader can block with hiz light zaber...)
Win
7 Not zure...
8.Exar Kun.
9.Darth Caedus
10.Darth Plagueis.
At thiz point he looze...
Stops at 5.
Originally posted by The Merchant
I thought the Emperor's Wrath>Dark Council Members, including Nox.
Besides, Emperor's Wrath not just benefits from his own great power and skill but also from being in such an important position. Eliminating Emperor's Wrath will invite wrath of Emperor himself. Of-course, Sith do not hesitate to fight when it becomes necessary but outcome of such confrontations leave an impact on others.
Emperor's Wrath (I) was immortal and killed hundreds of powerful Jedi and ambitious Sith. In a span of centuries, only HoT proved to be a match for him.
Emperor's Wrath (II) have hype of being as good as Exar Kun, if not better. Undoubtedly, he have incredible accomplishments under his belt and an entire story dedicated to his development in SWTOR.
---
Nox draws on the power of ghosts to bolster the effectiveness of his attacks, I don't think that it is wise to consider him for versus scenarios. The manner in which he dispatched Thanaton (one of the most powerful Sith of the Order) is really telling.
Originally posted by carthage
I don't think power will make so much of a difference as skill, Malgus's base telekinetic showings are still inferior to Vader's. Malgus is still slower and less skilled overall
---
Aryn Leener's raw power:
Aryn gestured at a cargo tram near the three men shooting at them from behind. The six cars of the tram rushed toward the men, propelled by Aryn’s power. They scrambled aside, and Aryn and Zeerid dashed for Fatman.
From (Star Wars: The Old Republic: Deceived)
Q: You realize what a cargo tram is?
And yet, Malgus could overwhelm her with his telekinetic abilities:
Malgus bounced up from the somersault and loosed a telekinetic blast that lifted Aryn from her feet and blew her across the hangar.
From (Star Wars: The Old Republic: Deceived)
---
Satele Shan's raw power:
No issue with destroying gigantic and extremely heavy objects. In-fact, Shan performed this feat with gesture from a single hand while being pressed on the ground by Malgus during the duel to break the deadlock between them.
Aldeeran-ian trees are enormous. They would weigh hundreds of tons on average, based on depicted size factor.
And yet, Malgus could overwhelm her with his telekinetic abilities:
Malgus comfortably shoved Shan into another gigantic tree with his telekinetic abilities.
Source: SWTOR Hope cinematic trailer.
---
Zabrak powerhouse's raw power:
The Jedi held his ground. At twenty meters, the Jedi raised his lightsabers aloft to either side and drew them both down with a flourish.
Too late the rumble of the falling buildings penetrated the haze of Malgus's anger. An avalanche of duracrete and transparisteel crashed down on him from either side of the street...
From (Star Wars: The Old Republic: Third Lesson)
NOTE: This guy collapsed two buildings around Malgus's position. This is one of the greatest display of raw power in the mythos. Vader doesn't have any showing of comparable magnitude.
And yet, Malgus could overwhelm him with his telekinetic abilities:
Malgus loosed a furious series of overhand strikes that forced the Zabrak to retreat rapidly. Sidestepping a stab from the Jedi, Malgus rode his motion into a Force-augmented spinning side kick that hit the Jedi in the ribs and sent him cartwheeling into the wall of nearby building. At the same time, he reached out with the Force for the hidden light-side user, brushed aside the resistance he felt, and pulled the Jedi out of hiding.
From (Star Wars: The Old Republic: Third Lesson)
---
NOTE: Malgus have lot more under his belt.
Darth Sidious noted that Malgus was an exemplary warrior and that his battlefields have never been duplicated, based on the information and archives he had at his disposal. And Sidious knows Vader very well.
Simply put: Malgus >> Vader
Vader is very good, but assuming that he is a match for Malgus is really a stretch.