Registered: Apr 2008
Location: Bringing forth the apocalypse
DN Luke displays truly incredible proficiency with the force. You can ask Faunus or Gideon. They can explain it a lot better than I can.
Still, Sidious- even when empowered by the dark side and being at his second most powerful incarnation- can not beat the arguably most powerful combatant in history. Only DE Sidious stands a considerable chance (And DN Luke is still more likely to take this).
Technically, Palpatine participated in two duels in the span of thirty-seven-years. That he only wields a lightsaber, ostensibly, to "humiliate the Jedi," one would assume that even with Malachor's enhancement properties, the Emperor will still prove to be no match for the former General in terms of swordsmanship.
In terms of Force usage, I'm not obligated to speak. How potent is Malachor? What sort of enhancement does it give its dark siders? That Palpatine is still revered (as is Darth Vader) even in Legacy of the Force, with Jacen Solo being described, at his peak, that his powers have "even surpassed those of his grandfather, Darth Vader" would imply great things.
But more to the point, the Emperor cannot compete with Skywalker in terms of bladework. If he is more powerful than Skywalker, even on this environment, I doubt it is to the point that he will crush him. So, with that in mind, I would say that Skywalker would win.
It, however, would most certainly not be a quick or decisive battle.
DE Sidious on Malachor versus DN Luke? Speak for yourself.
Well Malachor was the breeding ground for the Sith in KOTOR II its Dark Side energies surpass that of even Korriban I'd recon. But not as much as say... the Star Forge
This is the same man who took on Raynar Thul - a being powered by the Force-potential of an entire hive of creatures - and defeated him in seconds, after being hurled down a hallway and into a steel wall with enough force to split his helmet clean in half and put a visible dent in the wall's surface. The same man who entrenched himself so deeply in the Force that not even the black hole at the center of the galaxy could move him (hyperbole, sure, but impressive nonetheless).
Luke is faster, a far greater swordsman - Sidious at this point is far from the top of his dueling game - and vastly more powerful than the Emperor. The only reason this may last very long at all is the likelihood of a dark side boost from Malachor. Vjun's aura - which is likely far less steeped in darkness than the very storehouse of ancient Sith knowledge, and the site of one of the most violent battles in history - allowed Dooku to enhance his own ability to call on the dark side, so I suspect that a more powerful being on a tremendously darker planet would be able to do so as well.
Of course, the Emperor has access to techniques that Skywalker has likely never even heard of - not that the opposite may not be true, if "emerald lightning" is accounted for - while also having infinitely greater training in the Force, and is decidedly a more cunning warrior. I wouldn't say that he actually has a shot at winning this, but he could make it very close, especially with Malachor serving him.
EDIT -- And seriously, chill with the Luke/Sidious threads.
I'm sure someone will try to stab me, but I just want to throw this out there:
Some points, my NEW APPRENTICE:
a.) Didn't you say that RotS Sidious would challenge Skywalker? There'd "be an actual fight" or something were your words, as I recall.
b.) If 'a' is true, you do recognize that Palpatine is even more powerful in the Force?
c.) You do realize that even during Legacy of the Force the likes of Vader and Palpatine are still revered? That Vader is still used as a measuring stick to describe Jacen at the height of his powers means a lot.
d.) That same Jacen, while certainly not his uncle's equal, managed to inflict damage to him despite the fact that Luke Skywalker was majorly pissed and attacked him without warning.
This is addressed to you. Refute them and I shall flee to my lair, tail tucked between my legs.
I see that is the way of the force...mom jokes. Anyway back on topic! I'd definately say DN Luke takes this Sidious probably has not brushed his hand over his saber in over twenty years by now. I'd say it depends on the setting cause if Luke closes the distance(which I believe is possible) then he has this in the bag.
Registered: Apr 2008
Location: Bringing forth the apocalypse
Like you said, there's no way for us to gauge the level of empowerment Malachor provides to Sidious. While I guess DE Sidious can win on Malachor, he, regularly, is an inferior combatant in comparison to DN Luke.