After the Downfall of Númenor, Elendil led the survivors of the Elf-friends back to the North-western shores of Middle-earth. There many already dwelt who were in whole or part of Númenórean blood; but few of them remembered the Elvish speech. All told the Dúnedain were thus from the beginning far fewer in number than the lesser men among whom they dwelt and whom they ruled, being lords of long life and great power and wisdom. They used therefore the Common Speech in their dealing with other folk and in the government of their wide realms; but they enlarged the language and enriched it with many words drawn from elven-tongues.

For so we reckon Men in our lore, calling them the High, or Men of the West, which were Númenóreans; and the Middle Peoples, Men of the Twilight, such as are the Rohirrim and their kin that dwell still far in the North; and the Wild, the Men of Darkness.

With regard to Middle Men Faramir spoke mainly of the Rohirrim, the only people of this sort well-known in Gondor in his time, and attributed to them actual direct descent from the Folk of Hador in the First Age. This was a general belief in Gondor at that time, and was held to explain (to the comfort of Númenórean pride) the surrender of so large a part of the Kingdom to the people of Eorl.

...

Thus it came about that the Númenórean term Middle Men was confused in its application. Its chief test was friendliness towards the West (to Elves and to Númenóreans), but it was actually applied usually only to Men whose stature and looks were similar to those of the Númenóreans, although this most important distinction of 'friendliness' was not historically confined to peoples of one racial kind.... Also it must be said that 'unfriendliness' to Númenóreans and their allies was not always due to the Shadow, but in later days to the actions of the Númenóreans themselves.

After the return of Eldacar the blood of the kingly house and other houses of the Dúnedain became more mingled with that of lesser Men. For many of the great had been slain in the Kin-strife; while Eldacar showed favour to the Northmen, by whose help he had regained the crown, and the people of Gondor were replenished by great numbers that came from Rhovanion.

There’s one exception that puzzles me—Berúthiel. I really don’t know anything of her—you remember Aragorn’s allusion in Book I (page 325) to the cats of Queen Berúthiel, that could find their way home on a blind night? She just popped up, and obviously called for attention, but I don’t really know anything certain about her; though, oddly enough, I have a notion that she was the wife of one of the ship-kings of Pelargir. She loathed the smell of the sea, and fish, and the gulls. Rather like Skadi, the giantess, who came to the gods in Valhalla, demanding a recompense for the accidental death of her father. She wanted a husband. The gods all lined up behind a curtain, and she selected the pair of feet that appealed to her most. She thought she’d got Baldur, the beautiful god, but it turned out to be Njord, the sea-god, and after she’d married him, she got absolutely fed up with the seaside life, and the gulls kept her awake, and finally she went back to live in Jotunheim.

Well, Berúthiel went back to live in the inland city, and went to the bad (or returned to it—she was a black Númenorean in origin, I guess). She was one of these people who loathe cats, but cats will jump on them and follow them about—you know how sometimes they pursue people who hate them? I have a friend like that. I’m afraid she took to torturing them for amusement, but she kept some and used them—trained them to go on evil errands by night, to spy on her enemies or terrify them.

Now the descendants of the kings had become few. Their numbers had been greatly diminished in the Kin-strife; whereas since that time the kings had become jealous and watchful of those near akin. Often those on whom suspicion fell had fled to Umbar and there joined the rebels; while others had renounced their lineage and taken wives not of Númenórean blood.

After the return of Eldacar, the blood of the kingly house and other houses of the Dunedain became more mingled with that of lesser Men...The mingling did not at first hasten the waning of the Dunedain, as had been feared...

"It was the pride and wonder of the Northern Line that, though their power departed and their people dwindled, through all the many generations the succession was unbroken from father to son."

"I will not bow to such a one, last of a ragged house long bereft of lordship and dignity."

"though the length of the lives of the Dunedain grew ever less in Middle-earth [i.e., ALL Dunedain, whether in Arnor, Gondor, or Umbar], after the ending of their kings the waning was swifter in Gondor..."

did not cross the Isen nor take refuge in the great promonotory between Isen and Lefnui that formed the north arm of the Bay of Belfalas, because of the "Púkel-men," who were a secret and fell people, tireless and silent hunters, using poisoned darts. They said that they had always been there, and had formerly lived also in the White Mountains.

I think "Men of the Twilight" is the fluid label depending on one's allegiance to Gondor, and let's not forget that the Northmen used to fight Gondor, so when they were enemies, they were probably called worse names.

So it's not just the royal house but the nobility that are vulgarizing the precious DNA of Numenor, yet no one says "And this is when Gondor fell from the ranks of the Numenor and became a lesser folk, destined to decline." Nor is Eldacar saddled with a title like Elrond's (Half-Elven), or not that we know of: the Half-Dunedan or Half-Numenorean. And think of the implications of how that Numenorean blood gets diluted over time. He was 50% Numenorean, but let's fast-forward a few generations and assume a King of Gondor is only 12.5% Numenorean. How are they reckoned? As a Numenorean, through and through, not a Man of the Twilight.

Or do we assume that Gondor lived in a self-imposed fiction of "we're still Numenorean" because the alternative was too unappealing to admit?

Since the victors wrote the history, we don't know much about Black Numenoreans' point of view, but I will speculate that they had the same view. I think the key point of calling oneself Numenorean is the pride in descent from people who had lived on Numenor, presumably traced father-to-son. Or mostly father-to-son. It does seem that Beruthiel, despite her moral deficiencies, was rated as a prize bride both for her Numenorean DNA and for whatever lands she controlled via her noble/royal status among the Black Numenoreans, so a woman's racial purity matters, of there wouldn't have been the Kin-Strife over Eldacar. But it seems to matter less. There's this part in Appdx A:

would conclude that there was always tension in Gondor between the notion of true racial purity and the status one held, which Denethor conveniently expresses for me in "The Pyre of Denethor" as he disparages Aragorn while aware of his lineage:

Thanks for all that; I admit I'm rarely up for excessive speculation about Middle-earth that draws too heavily on real-world similes or examples to fill in the holes. One reason is that there are too many ways in which Middle-earth seriously differs from our world; and another is that Tolkien himself admitted to winging this kind of thing (historical back-story, geopolitics, etc.) by cribbing from Gibbon or the like, or trying out an old historical trope about imperial politics to see how it flies in the context of his story.

For an example of the first type of issue, I usually consider that 'DNA' with all its associated notions of genetic inheritance, is the wrong way to analyze Tolkien's ideas about his fictional royal lines. For whatever satisfying reason, in Middle-earth the father's genetic inheritance - oh, what the heck, let's just say "blood" - is far more important in estimating a descendant's worth than is the mother's. Thus Aragorn's multi-generational descent from Earendel and Elwing via Elros should count for almost nothing in relation to Arwen's elvish nature, yet the story says the two lines were 're-united' when they finally married.

Unless it's the other way around! Such as when all those Elvish wives marrying mortal husbands managed to bestow far more than a nominal 50% Elvishness, which ought to have declined exponentially by each mortal generation that followed, on their descendants many centuries later.

So although I agree that you can make some excellent speculations on just what Tolkien meant by "Numenorean blood" in the histories of Gondor and Arnor, because he clearly meant something by the term, the only thing I can really derive from it all is that the virtue of Numenor, being based on the Elvish connection, declined in Middle-earth as much due to the effect of being back in "mortal lands" as to the fading moral excellence of the ruling dynasties.

On another point entirely, I often see references in commentaries in this area to "Harad" as if it were some kind of kingdom - or, as you put it, a coherent federation of allied kingdoms. I think the confusion is that Harad is on the map right next to Gondor, which is an honest-to-Gosh kingdom, so Harad must be a kingdom like Gondor. But Harad just means "South" and should really be given the proper article The, as in The South. That more accurately translates it as the equivalent of real world European references to The East as a placename.... We ought to think of Harad that way, I believe: it's simply a catch-all term for everything to the south of Gondor, or more correctly, to the south of the lands of the Free Peoples of the Northwest of the Old World. (Rhun, of course, is the same thing: it's The East, not a kind of country called Rhun).

"The North" must refer to the North-western regions of Middle-earth, in which most of the inhabitants or speaking-peoples were and remained uncorrupted by Morgoth or Sauron. In those regions resistance would be strongest to the evils left behind by the Enemy, or to Sauron his servant, if he should reappear....

...Harad "South" is thus a vague term, and although before its downfall Men of Númenor had explored the coasts of Middle-earth far southward, their settlements beyond Umbar had been absorbed, or being made by men already in Númenor corrupted by Sauron had become hostile and parts of Sauron's dominions. But the southern regions in touch with Gondor (and called by men of Gondor simply Harad "South", Near or Far) were probably both more convertible to the "Resistance," and also places where Sauron was most busy in the Third Age, since it was a source to him of man-power most readily used against Gondor.

‘The loss of Umbar was grievous to Gondor, not only because the realm was diminished in the south and its hold upon the Men of the Harad was loosened, but because it was there that Ar-Pharazôn the Golden, last King of Númenor, had landed and humbled the might of Sauron. Though great evil had come after, even the followers of Elendil remembered with pride the coming of the great host of Ar-Pharazôn out of the deeps of the Sea; and on the highest hill of the headland above the Haven they had set a great white pillar as a monument. It was crowned with a globe of crystal that took the rays of the Sun and of the Moon and shone like a bright star that could be seen in clear weather even on the coasts of Gondor or far out upon the western sea. So it stood, until after the second arising of Sauron, which now approached, Umbar fell under the domination of his servants, and the memorial of his humiliation was thrown down.’

1) Even though Ar-Pharazon persecuted them ruthlessly and caused the destruction of Numenor, the Faithful were still proud of his accomplishment in humbling Sauron. Especially for Americans right now as they debate who is and isn't worthy of having a public statue when one takes the full measure of their successes and failings, it's interesting that the Faithful gave him a pass on their own suffering at his hands and singled out his battle-less victory, I suppose saying, "This was how great Numenor was at its height, now forgot the rest." To me it seems like a pan-Numenorean Pride statement, which leads to:

2) An exact date for the pillar's destruction isn't given, and I don't intend to quibble about this, but it seems possible the Black Numenoreans viewed the pillar with the same pride, and it was only when Sauron's direct lieutenants showed up in Umbar that it was torn down to appease them.

Thus it was that because of the Ban of the Valar the voyages of the Dúnedain in those days went ever eastward and not westward, from the darkness of the North to the heats of the South, and beyond the South to the Nether Darkness; and they came even into the inner seas, and sailed about Middle-earth and glimpsed from their high prows the Gates of Morning in the East. And the Dúnedain came at times to the shores of the Great Lands, and they took pity on the forsaken world of Middle-earth; and the Lords of Númenor set foot again upon the western shores in the Dark Years of Men, and none yet dared to withstand them.

Late for me too. I am of course speculating on the King’s Men, their depth of Melkorism, and the pride in being Númenórean. I guess I was thinking of situations like Vichy France, where a faction of the French accepted German rule, but they didn’t become total slaves and rename all their streets with German names nor empty the Louvre of its treasures to send to Berlin. Their are limits.

So the real temptation is to wonder if those extreme seafaring Númenóreans settled all around the world, or even sent emissaries as teachers and civilized students, as they did before they became conquerors, and did they influence these unknown, non-aligned realms in some way.

At this point I'm basically listing off fanfic ideas but I think it's to Tolkien's credit how huge his Secondary World feels and how many hints there are of even more lands and peoples beyond the (already vast) ones he wrote about in detail.

In the marshlands of the mouths of Greyflood and Isen lived a few tribes of 'Wild Men', fishers and fowlers, but akin in race and speech to the Drúedain of the woods of Anórien.

On another point entirely, I often see references in commentaries in this area to "Harad" as if it were some kind of kingdom - or, as you put it, a coherent federation of allied kingdoms. I think the confusion is that Harad is on the map right next to Gondor, which is an honest-to-Gosh kingdom, so Harad must be a kingdom like Gondor. But Harad just means "South" and should really be given the proper article The, as in The South.
...
(Rhun, of course, is the same thing: it's The East, not a kind of country called Rhun).

1) Even though Ar-Pharazon persecuted them ruthlessly and caused the destruction of Numenor, the Faithful were still proud of his accomplishment in humbling Sauron. Especially for Americans right now as they debate who is and isn't worthy of having a public statue when one takes the full measure of their successes and failings, it's interesting that the Faithful gave him a pass on their own suffering at his hands and singled out his battle-less victory, I suppose saying, "This was how great Numenor was at its height, now forgot the rest." To me it seems like a pan-Numenorean Pride statement, which leads to:

2) An exact date for the pillar's destruction isn't given, and I don't intend to quibble about this, but it seems possible the Black Numenoreans viewed the pillar with the same pride, and it was only when Sauron's direct lieutenants showed up in Umbar that it was torn down to appease them.

I should have thought the Black Numenoreans would be more inclined to through down such a momument.

Variag is a Slavic word derived from Norse Varingar "mercenary people" (vár "contract"). The Varangian Guard were Norse body-guards of the Byzantine Emperor.

It has been suggested that Tolkien adopted the Slavic term to indicate that the Variags were possibly mercenaries serving a possible Lord of Khand.

About Khand I guess it does not need to be Sindarin, but if it is it probably has some meaning like Harad or Rhun.

If it is not maybe it has some connecton with the name Khamûl which at least share the same spelling.