Sakura and Shirou
Sakura nodded in understanding. Seeing that the girl was obviously uninterested in the political workings of the city, she skipped the rest of her lecture, and instead moved to informing the girl of the things that would be important to her.
"OK, well, the most important thing for you to know right now, I think, is the registration system. Since people simply appear in the Nexus from their own worlds, it doesn't have any kind of official citizenship system or other residency restrictions. However, the chiefs do like to know who is present, so there is a registration system. It's not, strictly-speaking, mandatory to register but, if you don't, then it means there is no record of you being here, which means that employers, people renting houses and so on can't check up on you, so many of them simply won't take the risk. And, it also means that you can't get any help from the government since, as far as they're concerned, you don't exist. There's really no disadvantage to doing it, either, so you should register as soon as possible", she said.
"Yes, she's right", Shirou added. "If you want, we can show you where to go."