"If you can make cancer treatments of the kind a tinker might produce, there's a lot of need for that. Here especially," says one of the Ministers. Health, probably. "How reproducible is it?"

"Entirely reproducible! Again: not a real tinker. It's faster for me to just make a warehouseful of any given thing, but I have lots to do, so, law of comparative advantage."

"We will have to convince people to use it. Saying it comes from a strange parahuman who is definitely extremely powerful and probably not lying about what it does might take some doing."

"Yeah, I understand. I mean, I can also explain how it works. I don't have to make any of the components at all if that helps. But I do not have to ship the cure for hepatitis to every continent literally tomorrow."

"I'm glad you agree. I imagine you suffered awful brain drain from the remaining population after the disaster; do you have or can you potentially import doctors and engineers and so on?"

"Under normal circumstances no. Very few. But if we're suddenly offering the best laboratories and the chance to produce tinker technology that actually makes sense, it becomes more doable. This does depend on you being correct about the difference between you and every other tinker."

"I'm afraid nothing novel to you that I can make is also simple enough to teach you to assemble here in this room unless you want to trust me on the parts being exactly what I say they are, so we're back to square one there, but I can get you started on offering attractive working conditions."

It goes on the list next to power generators and repaired (or replaced) roads. Lower on the list, since reversing brain drain is not the kind of thing anyone was expecting to get around to any time soon and the blueprints don't currently exist, but still.

Practicalities time? Practicalities time. Cam recommends tidecatchers. They are an island and nuclear plants would be a big target for more Endbringers; tidecatchers are pretty harmless and will serve. And what are their power needs and projected power needs...? All right, that will require so many catchers and the following equipment to get what they catch onto the grid. He can't offer very much internet upgrade and still have them connected to the outside world, but he can do some, and lay down infrastructure for 2157 quality network within Japan itself if they'll kindly tell him where to put the stations. Roads he can do but is possibly not very efficient at doing unless they want all their roads to hover; he'd have to overfly the areas to get everything flush with preexisting matter. He can tell them how to maintain a hovering road system but they might not want to rely on that what with Endbringers plus brain drain.

Cam can totally copy buildings! And if their budget is lacking he can also make stuff that other countries want for Japan to sell. Wealth generation: not the same thing as inflation.

As it happens, duplicating Japan entire is a really bad idea. What with the unusually deep oceanic trench right next to the existing Japan, putting islands there would do a lot worse to water levels than re-raising Kyushu did. But there's plenty of improvements to be done on the original. The infrastructure ministry will be able to keep Cam as busy as he wants to be, getting gradually more creative as they have more time to think of useful applications of conjuration.

Good! Cam likes being busy. And he will drink all the coffee he needs to to continue being so.

Assistants yes, human yes, trustworthy depends on what for (they're probably reporting to the prime minister unless Cam wants to take the trouble of hiring his own), and of course no one knows the importance of the chalk.

And the circle gets completed by Sousuke, certified human.

The city of Takamatsu, plus or minus a decade. Cam's summoner is about as far southwest as anyone still lives, or at least he was before Kyushu's grand reopening.