"Hello," he says when they walk in. "Apparently everyone hears what's said as their native language, which makes no sense and is the sort of thing a person who knows nothing about magic would decide magic could do. Who are you?"

"Um," says Bella. "Hi. That sounds like a perfectly reasonable thing for magic to do to me? Where are we? I'm Bella and this is Fëanáro."

At that he turns around. 

It's - Loki, or a shorter Loki, and in fact someone who looks vaguely like what he remembers of - 

"How did you give me six books of explanation and not mention that you can do time travel?" he demands of the bar. 

...Bella recognizes him too, apparently. She squeezes the smaller instance of him a little closer.

As I have said repeatedly, I am not personally in control of most bar features, says the bar, and this is not time travel per se but rather a matter of an alternate universe.

He turns around. "Hello," he says to Bella. "You're holding me. Can you set him down? He'll be curious about the bar and I have lots of reading material for him." And to Fëanáro, "it's an interdimensional bar. I feel like my intelligence is being insulted but apparently no time passes back home so at least I'm not getting behind on anything important. How are you, what's she doing here?"

"D'you want me to put you down?" Bella murmurs.

"Yes." But a little apprehensively. "Are you the future version of me who killed a lot of people?"

"Yes," he says dismissively, "but it was necessary and they're back."

Bella puts the smaller of the Fëanors down.

"Necessary? Back?"

"I'm curious how you heard what happened, I didn't know when I was your age or I'd have been able to invent enough ways to prevent it. The Valar pardoned Melkor. He murdered our father and returned to torturing everyone in the Outer Lands to death, slowly. I amassed an army and went to stop him. Some people tried to stop me. Then we fought Melkor and we stopped him and my instance of the person you are calling Bella managed to free orcs and get all the dead released and round the planet and put us in touch with the rest of the galaxy, where we've commenced rescuing everyone in need in it."

"You have an instance of me? I'm not even from Arda. An Arda."

"Nor was my instance. She's Asgardian. Well, technically a frost giant."

"...well, I'm not. Either of those. We know what happened because the Valar told me."

"Did they tell you that we stopped Melkor and that doing that six months slower would probably have meant half a million more people tortured and that the dead were all back within three Years?"

"No, it was kind of patchy. And I definitely would have remembered if another me had featured. Also there was a part where you died."

"That's when the other you showed, actually. Maybe your instances arrive to disrupt whatever the Valar anticipate, even if they pick different times. Though I would have left the war in capable hands. We have seven children," he says to the smaller Fëanáro.

"I wanted ten."

"Your wife will want to stop at seven. And they're seven excellent children, worth two of ordinary ones."

"I'm... not sure at all you should expect this one to wind up the way you did even if you had a very good reason."

"Oh?"

"I, uh, disrupted. Things."

"Oh, no, did you murder the Valar? Loki seriously considered it."

"Nnnnno the Valar are all still alive - Loki? That's the other me's name? - but they kicked me out of Valinor for disrupting too many things and my Fëanáro rescued me from my evil universe and now we live in a third one."

"Ah. Hmm. Well, maybe he can come here and meet the people who would have been his children. You'll like them. What universe do you live in? How do you hop them? I and the children can come visit you, we have an interdimensional teleport that ought to do it. What makes a universe evil?"

"I've been calling my plane Materia, wizardry does the trick if you can work on it in amenable conditions, and my native plane is both full of relatively ordinary hazards and also systematically and enforceably opposed to the concept of science."

"Hmm. So - we were going to go places, drop a lot of artifacts that are directional teleports to somewhere safe, with instructions about how to use them - will that go wrong if we drop them in Materia?"

"Not necessarily - the problem with the place is that it hates being predicted and accordingly I can't make any truly reliable predictions about it. It didn't squish me when I went back having done science, but I didn't try to do any there, and when Fëanáro came to get me he'd already developed his spell safely outside of it and then I distracted him with a language textbook while I packed, so - I don't know. Uh, but you may not want to let arbitrary inhabitants of my universe out."