One of the men, who's wearing tight-fitting red-and-gold armor from the neck down, greets him in a language he can't understand, though he can read just enough of his thoughts to get the meaning of the words.

"Hey. So you're the new wizard. I'm Tony Stark." He holds out his hand to shake.

Leareth tenses slightly - he's been generally on edge, and thus especially isn't in the mood to touch strangers who he's just met - but he follows Tony's lead and shakes his hand. 

:To clarify, I do not actually speak your language. Yet. If you deliberately think words at me then I will pick them up: 

He would normally be so curious about the nonhumans and their alien magic, but curiosity is very tiring right now. 

Tony recognizes Leareth's discomfort with the handshake, and makes it a short one.

"I know. I'm saying things aloud while thinking them at you to help you learn English," he says-and-broadcasts. "It worked really well for the elves. Don't let them know you speak a new language, though, they're easily distracted enough as is.

"By the way, I didn't catch your name—I can't just call you 'wizard' now that there's more than one of you—"

It's too late; the elf with the non-organic body hears "new language" and his attention is immediately caught. He turns toward Leareth, and Leareth notices—he doesn't know why he didn't notice this before—that the elf has three extremely powerful magical artifacts apparently—embedded in his chest?

"I promise not to annoy you with questions about your language if you'll speak it aloud while thinking things at me like I'm doing now, instead of just saying everything over osanwë," he says-and-thinks the same way Tony did. (The last word carries a mental connotation of basically-but-not-quite-Mindspeech.)

"I'm Curufinwë Fëanáro, by the way; Fëanor for short," he adds. He doesn't bother attempting a handshake. "This is my son Curufinwë Atarinkë, and Calanáro Imbírtan, who isn't related but probably wishes he was." He gestures to the other two elves as he introduces them.

The other elves look briefly at Leareth as their names are mentioned, then go back to their work.

Having to learn an entire new language, on top of everything else, sounds so exhausting. Leareth tries not to look too visibly weary at the suggestion. Maybe he can throw Nayoki at the problem, she's faster at picking up languages since she can cheat with Mindhealing. 

"I can do that," he says out loud in Valdemaran, while echoing it in Mindspeech. "My name is Leareth." He's not going to bother unpacking the difference between Velgarth mage-gifts and whatever it is that Strange does. "Doctor Strange said that you could explain where your research is at right now, with the - shrinking, and time travel, and the limited supply of particles that allow this?"

Being socially graceful is going to take more energy than he has right now. "Fëanor, I cannot help noticing your powerful magical artifacts - what are they?" Vague gesture at the elf's (artificial?) chest. 

"Okay. Quantum Physics 101 for Wizards." He starts typing on his computer terminal as he speaks, bringing up visual aids on the holo-display. "Space and time are different dimensions of the same fundamental thing, which can bend—for example, this normally happens if you travel really really fast, although not in a way that's useful to us. However, at a very small scale, twenty-something orders of magnitude smaller than an atom, the structure of space-time is...naturally twisted, in a way that we could potentially navigate."

He holds up a tube of some kind of red fluid. "These are Pym particles. They can...somehow change the scale of matter, potentially down to the scales where we could use the natural twisting in spacetime to travel into the past. The problem is that we don't have nearly enough of them, and their inventor is dead, and we don't really know how they work."

(The Pym particles aren't magical, except in the very basic sense that magic involves manipulating the universe at a more fundamental level than ordinary physics, and they're...something very fundamental that should not be existing in isolation, but they definitely weren't made by any Velgarth Gift.)

"There's another aspect of this problem, as well. The geometry of space at this scale is...extremely complicated, and navigating it without getting lost is a very difficult mathematical problem. The computers are doing most of the number-crunching, but they can't produce creative solutions—you might be better at math than physics, it requires a lot less context."

"These are the Silmarils. They capture the Light of Valinor, which is—an energy field that our gods created to slow the negative effects of time—we're immortal, see, and living in a world where everything else dies quickly is unpleasant. The actual light, as in radiation, is actually a side effect. However, it turns out that the principles the Valar used to make the energy field were quite general, and so the Silmarils are...quite a bit more versatile than is usually believed.

"Also, since I see you staring—no, this isn't my original body. I was resurrected by an unconventional method, and Earth didn't have the technology to produce a new organic body, although this is superior in most ways anyway.

"I've been operating on the assumption that Pym particles are something...in the same class as what the Silmarils capture. The stabilization medium is certainly similar to silma, although fluid and inferior in durability—the red color is just a dye added for presumably aesthetic reasons."

Leareth's head hurts. He can't tell whether this is because the concepts are genuinely hard or just because he's running on three weeks' worth of chronic sleep deprivation. 

"- I suspect I could work on the mathematical side of the routing problem, sure." It would be easiest to just do this, find a concrete problem he can absorb himself in and not think about any of the larger context, but that would be stupid. "The Pym particles - do not show up as directly magical to my Othersenses, at least not in a way that points at how I could make them, they are simply...odd, they ought not be stable and storable like this... The Silmarils do appear as very magically powerful. I might learn something from examining them more closely. Did the inventor leave any documentation on his research–"

Wait. Pause. He wasn't being nearly confused enough about the middle there -

"- Fëanor, you were resurrected? Was that - only possible because of your species' pre-existing immortality, or could it be done again - for example, to contact the inventor of the Pym particles...?" 

"Pym destroyed most of his notes after his invention killed his wife."

"If they're anything like the Silmarils, their design may not be the sort of thing that can be documented, anyway. But I will allow you to examine a Silmaril, under my supervision. They can be—extremely dangerous if tampered with badly.

"Normally the souls of mortals pass beyond the world and cease to exist within it; if they are preserved in some other place we do not know where or how. However, my understanding is that Mandos, who keeps the Halls of the Dead that are within the world, is holding Thanos' victims specifically here, and is willing to resurrect anyone who can contribute to the fight. I'm not sure how we'd contact him, though."

Tony shows Leareth the basics of how to use the computer and loads up the spacetime geometry simulation for him to experiment with.

Leareth picks up the computer usage skills and the geometry simulation a lot faster than he's picking up English. Earth's current understanding and theory on physics is a lot more advanced than what he had managed in Velgarth, even over millennia; he doesn't think any of it contradicts his own understanding, it's mostly that certain confusing physical phenomena were only discovered once Earth's technology had advanced to a certain point. And Velgarth, for the obvious reasons, never made it that far. 

The math behind it is complex and elegant and beautiful – and there's no particular loss or anger associated with it, unlike literally everything else right now.

Even studying the Silmarils under Fëanor's supervision is painful, because he keeps imagining how awed and curious Vanyel would be. Leareth manages half an hour of this and then delegates that entire side of things to Nayoki and Savil. 

He very responsibly stops working at a reasonable time, puts thorough shields on whatever room they offer him to stay in, and tries to sleep. This is not especially successful, and well before Earth's dawn, he's back in the lab on the geometry-simulating software, staring at visualizations of the structure of spacetime at scales twenty orders of magnitude smaller than an atom. By the time the sun rises he has a pounding tension headache, but he's made a lot of progress on making sense of it, and he's trying and mostly succeeding at not having any other thoughts. 

Later that day, Fëanor makes a breakthrough, of a sort.

"I believe I have a working theory on the nature of Pym particles," he says. "However, to test it, I need equipment more advanced than what we have here. The particle collider in my laboratory in Valinor should be sufficient, but returning there will cost us significant time—subjective time passes ten times more slowly in Valinor compared with the rest of the universe," he adds, for Leareth's benefit.

(Also, he doesn't want to go there, specifically—the particle collider, being much too big to fit in the palace, is at his estate in the foothills of Aulë's country—Nerdanel's estate, now, and he's not sure whether it would be worse or better, at this particular moment, if she were among Thanos' victims.)

Fëanor was also working in what most humans would consider the middle of the night, which Leareth noticed in a distant-background sort of way and found vaguely reassuring. Leareth is wondering now if Elves just need a lot less sleep, though, because at this point he is definitely not operating at his best. 

Probably he should ask at some point if they have good painkillers here. Later. 

"The time-slowing effect seems worth avoiding! What are the capabilities that you need - I am wondering if our magic could help quickly build a sufficiently advanced setup more quickly. We were able to design and build the space capsule we travelled in with a week's lead time, and my people are more up to speed on Earth's tech now." 

"My particle collider is significantly larger than this entire compound and actually depends on some of Valinor's peculiar physics for more efficient energy generation. Even with magic I think we would spend more time building a new one here than we would waste performing the remaining experiments in Valinor."

He doesn't need to sleep much, but he knows something of human sleep patterns by now, and he knows that Leareth's are unusual, and not in a good way. "You would also—feel better there, I think," he adds. "I've never desired that particular effect, nor indeed slept long enough to notice it, but—'lands there are to west of West, where night is quiet and sleep is rest,' as the song goes."

Leareth gives him a briefly-very-suspicious look when he says the last thing. "All right. I expect it makes sense to leave most of my people here, then, where they can continue working with the other Avengers and getting up to speed on various things here."

After a brief pause, "- I would bring Shavri and Yfandes, I think, if that is acceptable. I am not sure either of them would be useful for the research aspect, but - they would benefit from the effect you describe." 

"Our ship should be more than large enough to hold our research team plus three others. It is not designed for...horse-shaped people, but it isn't a long voyage. I'm ready to leave immediately, if your friends are.

"Also, we should consider leaving someone here to continue running the geometry simulations without the time-slowing effect—I don't actually know if it affects computers—"

"It doesn't. I can communicate with Earth's internet without correcting for it at all. We should definitely be running the simulations there, our computers are much faster."

"Alright, then we'll all go. Unless there's someone who would prefer to stay here."

Both Tony and Bruce want to go.

Leareth wants Nayoki to stay behind and, in his absence, be in charge of the rest of his people and point of contact with the Avengers. 

Nayoki isn't especially fond of this plan! 

:Leareth, I am worried about you and I would prefer you not be alone on another planet: 

:I will be in the company of many other scientists: Leareth points out, very reasonably in his opinion. 

:You know what I mean!: