"Once these Halls were vast enough that one might never meet another soul if so one chose. Now they seem crowded. How is this so?"

"Thanos must have succeeded."

"Who?"

"Y'know," he says, as though it were absurd for whoever this is to not have heard of Thanos by now. "Yea high. Purple. Thinks he has to bring balance to the universe—by murdering half the population—"

"That is absurd. Not even my old Enemy could have done such a thing, and he certainly would have if he could."

"Infinity Stones tend to make the absurd possible. That's kind of their whole reason for existing, I think."

"Hold on."

This random stranger, whom he had kind of wanted to get away from, has just become about five orders of magnitude more interesting. Not, precisely speaking, in a good way.

"What exactly is an 'Infinity Stone'?"

"Uh, I'm not sure of the technical details. But they're some sort of primordial naked singularities, imprisoned in crystal by the arts of the Celestials before the dawn of time."

Well, the technical details are definitely a bit off. But the resemblance is well within the bounds expected for a 15,000-year-old legend, and it's unlikely that two sets of objects that similar would exist.

"I do not know you, stranger," he says, pride and rage and excitement conflicting within him, "but if you know these 'Infinity Stones' then you do know me, corrupt as the tale of their making has become. Their right name is the Silmarils, and they are my work.

"As well as my property."

"You're a Celestial?" He hadn't known it was possible for Celestials to die.

"No! That part is a vile and abominable lie; it seems that, not content merely to steal the jewels themselves, the jealous Valar now lay claim to their authorship. But it is not so. I am an Elf, a Noldo of the House of Finwë, called Curüfinwe Fëanáro at my birth and Fëanor in history, and the Silmarils are the work of my hands and mind, and no other's. This Thanos, if he has taken them and used them for unspeakable evil, has made of himself my sworn enemy: for even in death I am oath-bound to pursue with unrelenting hate him whoso keeps my sacred jewels from me.

"Who are you?"

An álf created the Infinity Stones? That doesn't exactly seem plausible. Probably there is a very significant miscommunication happening here somewhere.

But whoever this álf is, he's very powerful, if he created artifacts that even had the slightest chance of being confused with the Stones, and in his current state of confusion he considers himself obligated to fight Thanos. This miscommunication might be useful.

"I am Loki, of Asgard, and I am burdened with glorious purpose. Perhaps not quite as glorious as yours, I'm afraid."

("I am Loki, of Valinor," Fëanor will hear him say. Fëanor isn't yet aware that he's using translation magic that sometimes gets a bit overzealous with any proper noun that has an etymological equivalent in the target language.)

"Huh? You're not an Elf, or an Ainu, and I'm pretty sure you're not a Man, although I don't think those are allowed in ValinorAsgard anyway."

"ÁlfarElves live in AlfheimEldamar. I don't think they're actually native to it but I'm pretty sure they didn't come from AsgardValinor. Besides, how can you have heard of AsgardValinor and not recognize an AsgardianValinorean?"

...

"Okay, almost nothing in that sentence made sense, but for one, there's no such race as 'ValinoreansAsgardians', unless you mean the Valar, which you're definitely not."

And then he finally realizes.

"Hold on. I believe there is something very wrong with my translation magic—I actually didn't expect it to work at all in death—and I believe it has derived a false equivalence between our homelands. Let me turn it off, and hopefully we'll still be able to understand each other, since I'm pretty sure neither of us are speaking actual words anyway."

He deactivates his Allspeak.

Fëanor is easily distracted, especially by things like "translation magic".

"You have translation magic? Is it universal? How does it work? I tried to do something like that, a ring or something that would allow you to understand any language you heard, but it would need to be programmed with universal principles of grammar, and I only had basically two languages to study—although Valarin probably counts for at least three—so I couldn't really be sure what those were—"

"Yes it's universal, although it sometimes takes a little while to adjust to new languages, and sometimes it has bugs like the proper noun thing we were just experiencing—what, by the way, are the meanings of all the words you were trying to say to me that came out as 'Asgard' and 'Alfheim' and such—?

"I have no idea how it works. Most Asgardians get it installed as soon as we're old enough to speak."

"What sort of thing is it that gets installed? Like a Ring? An artifact?

"Valinor means the country of the Valar—the gods, if you will, though I've never found them particularly worthy of worship. Eldamar is Elvenhome—and 'Elda', Elf, breaks down to 'star-folk', we're also called Quendi which is 'speakers'—

"How many etymologically unrelated languages are there in your world?"

"Uh, it's a brain implant—keep in mind we don't have 'magic' per se, it's just very aesthetic tech that only technically doesn't violate the laws of physics—

"Asgard is the country of the Æsir, which is the proper name of our species—we tend to go by 'Asgardian' in mixed company because the singular form of 'Æsir' has an unfortunate resemblance to a vulgar Midgardian word for the buttocks—you seemed pretty sure that we don't resemble your Valar, but Asgardian is actually a language from Midgard that we speak for complicated historical reasons, and the people we borrowed it from did think we were gods, so that might explain some of the confusion.

"There's got to be millions of languages in the universe that's known to us—galaxies are big and we've explored two plus a few smaller satellite ones—but without Allspeak I know Asgardian and Vaniran and Álfish and pretty good English and a bit of Groot because ugh Thor—"

"Midgard is—'middle-country'—Endórë? Also millions of languages, I've really got to get out of here—could you say something in 'Álfish' and 'Vaniran'? I want to see something. I realize we're probably using some form of thoughtspeech, focus on the actual sound of the words instead of the meanings—"

"Is Endórë what you call the galactic backwater filled with useless humans that somehow manages to be the center of universal-scale events on a regular basis?

"This is a sentence in Álfish," he says, in corrupt but recognizable Sindarin.

"This is a sentence in Vaniran," he says, in nearly perfect Vanyarin Quendya.

"—uh, now that I think about it, I think those two are actually related."

"And this habitation might seem a little thing to those who consider only the majesty of the Ainur, and not their terrible sharpness; as who should take the whole field of Arda for the foundation of a pillar and so raise it until the cone of its summit were more bitter than a needle—" he intones—"which is to say, yes, basically, the apparent backwardness is by design, though I don't understand it.

"And okay, clearly some Elves got very lost at some point. What do you know about the 'Vanir'?"

"They look kind of like álfar, but taller, stronger, and blonder. My mother was of that people. Their king is called Yngvi."

"...Ingwë of the Vanyar," he corrects, "but seriously, this time: who are you and what have you done with my universe?"