"We assent to this, on the condition that no residents natively of this dimension travel to yours. We will make such travel impossible. We have also made the summoning of beings from your world to this one impossible."

...this is a deeply inadequate response and Cam has no idea if pushing his luck will somehow make them even more aggressively inadequate. "I am new to the world and do not know how your impossibilities work. I would not like to have to fear for the possibility that the Doom will escape if some person should do so in a fashion you do not anticipate. While of course controlling immigration and emigration is your prerogative I would rest easier on behalf of those billions of Limbo-destined souls if their safety from Doom were unconditional regardless of how the natives of this world behave. I have no way to warn them, not even if I go home."

"They certainly will not be subject to the Doom; it lies only on the House of Feanor and those who follow them. If a Doomed person reaches your dimension they will not cease being Doomed. Though our powers should not carry out their working in your dimensions, the distorted minds and passions of those so Doomed will remain. And their Doomed choices cannot be sealed off from affecting others. We can ensure that no one leaves this dimension for yours. That ensures the safety of yours. It is the only way to ensure the safety of yours."

"I am concerned that someone from here may reach my world and someone else may do something that constitutes 'following' them," Cam explains.

"The Doom shall be restricted to the Noldor and passed down by blood rather than allegiance."

"Thank you. - I am not familiar with how your proclamations work, is that pan-universal?"

"It is. Everywhere our powers stretch at all and the Doom is therefore relevant, this is now true."

Okay cool that is merely as inadequate as they were trying to be in the first place. "Thank you very much."

"Go with our blessing, stranger."

"Thank you."

And Cam gets up and goes out along the Too Many Gems Path.

And passes a few happy agreeable petitioners or observers, and returns to find an interested crowd around his spaceship. 

"Hullo," he says when he lands by his ship.

"Hello, stranger. Are you from another world that should be known to us? Eru spoke of no others."

"I am from another world! People from it are summonable and can be called up to do their summoners favors, but you shouldn't expect any more of me, the Valar decided to forbid further summonings when I spoke to them." And it was probably a fluke even before that but fucking Valar.

"I'm sure they acted wisely," the speaker says seriously. 

"Anyway, I'm not sticking around, I seem unnecessary on Valinor, so if you have questions about me ask 'em quick."

"Can you share some of the art and poetry of your world before you go?"

"It's not in your language, any of it," Cam points out.

"We may take a long time to come to appreciate it. Music might be easier to appreciate than poetry, if you think we'll struggle to learn your language?"

"My world has hundreds and hundreds of languages," Cam says. "But maybe you'll figure it out. Hang on a sec." He investigates his data conversion patch to see what kinds of formats he will want to render things in. "Is this a good place to put a large number of data storage items?"

"...sure. We can take them to the library from here."

"Okay, good, because my people are very avid collectors and producers of all sorts of art and music and writing and I see no reason you shouldn't have all of it."

And local-format data storage objects start appearing.

"I have incorporated what I've got so far on Quenya-to-other-languages translation in there, that should help. My personal recommendation is that you watch a good performance of Atriama. It's my favorite."

They are delighted. Cam is sincerely thanked by dozens of people, many of whom are actually crying. They promise to watch Atriama and also everything else and to compose lots of reviews if they'd be appreciated and there's any way to get them to the composers and performers.

"...you know what, there actually is. Just make sure you compile your reviews under the title 'submission to the Hell Curators' Association' - in Lagalann that's -" he translates it, writes it down for them, "with lots of metadata about where it's from. They routinely conjure up all submissions to their association and incorporate them."

They will be flooded with reviews from Valinor, then! Cam has their undying gratitude.