To get the answer:
Fight Vivec in Morrowind.
Fight Almalexia in Morrowind.
See which is more difficult.
The Hlaalu have the best morals of the Houses, even if they are also kind of corrupt. Hlaalu all the way.
Alter magical forces to bypass limitations of the physical world.
Manipulates the limitations of the physical world itself.
The most fine lines between the skills can be seen in Morrowind.
Their descriptions there are:
"Mysticism involves the manipulation of magical forces and boundaries to bypass the structures and limitations of the physical world."
"Students of the College of Alteration manipulate the physical world and its natural properties. Alteration effects include water breathing and walking, jumping, levitating, burdening, opening and locking, and creating shield barriers against physical damage."
Paarthurnax has been ''free to return to evil'' for over 3000 years at this point. That's a very poor argument you've made.
Paarthurnax says he knows he can be trusted, but that he understands why the Blades do not.
And I'm still waiting for the big reason as to why you so desperately want him to die.
Orcs, by a long shot, are the strongest race of Tamriel physically. In a fist fight, you can bet the Orc will come out on top.
If a proper fight, things might be different, since Nords and Orcs have different fighting styles.
There's more to it than that, not only do you need the Dark Brotherhood to train them, you also need the government (or King, if that still exists) of Black Marsh to employ them.
It's revenge on the ones who betrayed the Reach? They aren't doing it to change the society.
They do not use fear; their goal is military conquest. The fact that they do so in a bloody matter does not make them terrorists.
Why should they deserve to live? Because they're the natives? Only reason they turned this bloody is because of Ulfric and his Stormcloaks going on a rampage in Markarth in '76,
I do not like or dislike entire races, especially the elven races. They are incredibly diverse, even on their own.
The Dunmer can not be grouped into one race which you like or dislike, the Great Houses and Morrowind Factions are incredibly different. Having opposing viewpoints which even result in full-blown conflicts.
The Altmer generally share the view of supremacy, but even there conflict exists, or at least, existed before the Thalmor took over. Some being more open to foreign races, some being xenophobic nationalists, some being extremists.
I can't really speak much of the Bosmer, I know too little of their lore to make a conclusion on how diverse, or a lack of diversity, they have.
The Ayleids were also divided, half the reason they fell was because of this division; Daedra-worshipping Ayleids fighting among themselves, and against the Barsaebic - Aedra-worshipping - Ayleids. Their magical prowess and history is rich, even if their society collapsed under justified circumstances.
The Dwemer all seem to have shared the ideas of defying the Gods and aiming to achieve knowledge. But even in this conquest, they were divided. In Skyrim we had the Dwemer fighting over Aetherium, on Solstheim they tried to uncover the secrets of the Black Books, and in Morrowind, Kagrenac attempted to create the Numidium, and (possibly) turn the Dwemer into a greater entity.
The Maormer, while certainly more unified in their thinking than most, also deserve some sympathy. According to their story they were kicked from Summerset by the Altmer, and forced to settle in Pyandonea, and have sought to reclaim their rightful homeland ever since.
Even the Falmer deserve some form of sympathy, their society is said to have rivaled that of the Altmer, which is a feat in its own right. The claim that they attacked the Nords unprovoked appears flimsy, thanks to Gelebor's statements of constantly being at war with the Nords, the Eye of Magnus under Saarthal, and the Atmorans (according to myth) swearing ''blood vengeance on the heirs of Auriel for all time''. The Falmer, being elven, would be classified as ''heirs of Auriel''. From the few Falmer records that managed to survive the Nords, they seem to have been a rather peaceful people, forced into hiding by an agressor from the North.
The Forsworn are rebels, not terrorists. They aren't trying to ''change policies'' in the Reach, they aren't trying to force people to convert, they are trying to reclaim their homeland through war. That's not terrorism, that's rebellion.
Also, Dragons don't go to ''heaven'', the Gods in Tamriel are very different from our ''Gods''.
I'm still trying to figure out why Paarthurnax deserves to die. For killing those who wanted to kill him, or because he, for a time, aided in the ''enslavement of the Nords''?
If the former, does our Dragonborn deserve to die for killing Forsworn in the Reach?
Did the Dres deserve to die for enslaving Argonians? Despite releasing all of their slaves in the late-Third Era?
Your argument is flimsy. As said, Paarthurnax has already been forgiven by the very people he opressed. Would you argue that slavers should still be punished if their very own slaves forgave them?
I'm not talking about the Fourth Era, I'm talking about the Dragon War, which only ended up in a rebel victory because of Paarthurnax.
You say ''why should Paarthurnax stay alive?'', but the better question is, why shouldn't he?
He has already been forgiven by the very people who he had enslaved, and thus, there is no more justification for demanding his death. There is no justice in killing a being which has already been forgiven.
No, all Arngeir said was that Paarthurnax was on Alduin's side. Which was because you couldn't be against Alduin, Dragon or not, without Alduin teaching you a lesson.
The problem with your logic is that you aim to punish the very being who is responsible for justice even becoming a thing. Were it not for Paarthurnax, Alduin would not have been overthrown. Were it not for Paarthurnax, the people would still be enslaved. There is no justice in killing the being responsible for the salvation of the Nords.
Do we have specific evidence of Paarthurnax' deeds?
No. Aside from ''enslavement'', which is not punished by death.
Do the Blades have specific evidence of Paarthurnax' deeds?
Not that they provide at least.
Therefor, until we get new evidence, Paarthurnax is innocent of any accusations held against him.
Paarthurnax has always been defended by the Dragonborn, every Dragonborn dynasty defended him, yet now we stand against him? Because the Blades say something without proof?
Since when is merely fighting to defend yourself a crime? Paarthurnax was a Dragon, the Nords waged war against the Dragons. Do we know what Paarthurnax did before that? Nope. He killed Nords in self defense, but we have no evidence whatsoever that he played tyrant.
Just because you fought back against rebels does not mean you deserve to die once the rebels take over. Especially not when those very rebels forgive you. The Blades have no right to speak, considering they are going Dragon-genocide.
Paarthurnax hasn't done anything wrong since the Dragon War. He saw the errors in his ways. Why do you think he tries to convince others to follow the Way of the Voice after we defeat Alduin?
Does Paarthurnax deserve to die because he saw the light, and now wishes that other Dragons stop killing innocents?
The Imperials came and said that some 500 years ago when they first conquered Skyrim - after the Nords invaded Cyrodiil first.
Ulfric is a murderer, you do not kill the opponent in a duel for the throne.