Time passes.
When it's been a few decades, the Lord Ruler order to keep all new children's names secret starts to matter. The names of a noticeable fraction of the population are known only to their parents, so it's safe to start the emigration. There's already a portal to the steppes of course, to help with making absolutely sure there aren't any fairies occupying it, and Alendi sends out a call for (young) settlers. More and more people move, growing their own food before long, and in a few years there's a very successful colony.
(Over subsequent years the colony's population increases more and more. Moving isn't mandatory yet, but there's an empire-wide propaganda campaign based entirely on true information.)
And Fairyland is so pretty. And Promise and those she commands are so much nicer than the nobles.
While the second Final Empire is being established, the inhabitants of Scadrial's South Pole get invited to join. The planet will be completely empty in relatively short order.
(Promise discovers, about a hundred years after the Usurpation, that Scadrial is not in fact "the mortal world". The gate she made for the mortal she was trying to help back when Thorn caught her goes somewhere else. She doesn't tell anyone.)
There are minor hiccups and issues; they get fixed. The ex-queen starts calling herself Whisper. Promise and Arcane are adorably enamored of each other. Thorn continues to be a heavily restricted sparrow. Civilization creeps across the Steppes.
Over the centuries, the numbers of Inquisitors decrease. (Nobody's being killed for Hemalurgy, and there are only so many useful spikes to be passed on when existing ones die or retire.) But since some of the humans are learning sorcery, and much more collaboratively than most fairies, moving to Fairyland comes with a net gain in minion usefulness.
Alendi even finds out that his immortal minion, a man going by Dorian, was the donor for one of Promise's spikes. And that she has used tinminds he filled. And while that charge could theoretically be replaced, it can never be returned.
This has not occurred to Promise, or she probably would have taken some action about it.
A Queenscourt sorcerer makes a gate to the hidden room under the now empty palace.
Promise approves of letting Alendi handle this. He's done it before. And if he doesn't come back most of his useful features can be taken over by some other mortal.
And then Promise hears a voice she probably doesn't recognize say "No tin. No sorcery. Go through the gate. And quiet—but tell the Lord Ruler he can act freely."
Zinc is not tin or sorcery. Think think -
But she's already going through the gate, quietly -
There was no one with her -
No no no no -
"Don't bother trying to get to the Well first. If that would even help. I've got more charge in my metals than you, and am using enough zinc that I'm thoroughly bored. Now, the order?"
She isn't technically his master. If she were technically his master the wording would have let her not enforce that when she said it. But he is only obeying her as though she were his master; there's no distinction she can make. She speaks or doesn't; and when she speaks it works.
Back to being quiet and thinking furiously.
He enters the pool, and his body burns away as he ascends.
But the sorcerer has closed it. She doesn't know how long this takes; she'll be noticed missing but not for hours, damn her introversion.
Fuck. Fuck. She's not certain Ruin can kill fairies. But if she can't do sorcery... and without access to at least one of the other four, she can't - if it wrecks the planet under her feet then even when Alendi inevitably loses hold over someone who wants her back they won't know how to fix a gate on the rubble or void or slag. It might not leave her conscious to come up with more plans. She needs a plan now.
She sears through her zinc. What do I have. What do I have. What do I have.
Okay. The thing that's going to destroy the world is a mind. They were trying to reason with it. It wouldn't talk to them, but it can theoretically be talked to. She can't get to the place the other sorcerers were writing to it without opening the door (not an Allomancer) or walking through the wall (no sorcery), but maybe later it will be able to hold a conversation from here too.
It's called "Ruin" for a reas-
...It's called Ruin.
She's called Promise, but that is not her name.
And Ruin is not a fairy.
This is the longest long shot.
What is its name? If she has its name it can't destroy her so WHAT IS ITS NAME?
She runs out of zinc.
She thinks as the swirl of dust through the air accelerates.
Probably Alendi has already gone home through some other gate.
Okay. What does she know?
Its metal is called "atium". Not "ruinum."
Ati.
The name
snaps
into
place.
Promise is still trapped and still very much constrained. She can't even talk in case it can hear her; she must be quiet.
But she has its name and it cannot destroy her and that means she has more time to think.
Once on the other side, he starts recreating some of the things he missed from classical Scadrial. Everything from buildings to fruits and animals. (Especially the fluffy ones. Tell no one.) He also takes the trouble to replace every plant within his large but interestingly finite perception with an identical one. May as well collect an enormous number of vassals.
A fairy—he recognizes Arcane—seems to be angrily sorcering at the gate. He really shouldn't have been able to figure out what was going on. So Alendi turns him into a frog and drops him off several miles underground beneath a completely different city.
Then he lets go of the Shard. He leaves the power in a familiar glowing pool beneath a (new) hidden tunnel in his (new) capital, and leaves himself with some beads of lerasium on the off chance he wants them later. His sorcerer closes the gate at his order.
Meanwhile, Ruin leaves its prison. The room has gone dark when the pool disappeared, and now the walls and ceiling are audibly falling apart. It rushes off to the Pits of Hathsin, and finds a darker metallic pool full of most of its power. Finally, it can begin destroying.
Promise flings her hands over her head. This is not good for her hands, but it keeps her conscious until there's enough of a gap in the wall to slip through. She needs to get into open air or she won't be able to command Ruin when it finds that it can't destroy her. She knows the place, if at a bit of a remove and in a less collapsing state. Out she goes. She's allowed to fly, so she flies.
She hears a voice coming from all of the air around her, Why can't I destroy you?
She was told to be quiet, not silent. Alendi didn't blink when she produced footsteps and breaths and heartbeats. She can murmur. Right?
"Hold," she whispers. Queen's phrasing, not Thorn's, not Alendi's. Work. Work work work work work -
She lands on the still ground.
"Listen to me," she says. "You may, truthfully and completely and without attempt to deceive me or drown out my voice or distract me from tasks, and without via any mental circumlocution permitting these things to happen as a side effect, answer my questions. Are there any other people left alive in this world?"