"...I see. That would make a constantly growing population less of a problem. Our world is not infinite and theoretically it would be possible to overpopulate it, eventually, if everyone were immortal and also children were still being born." 

"We're on one of those round things? A planet?"

"Yes. You have heard of planets, then - is this other mortal world also a planet?" 

"Yes. They call it Earth."

"Do you know much about what Earth is like, aside from lacking magic?" 

"Not that much, and all of it second- or thirdhand."

Nod. "I think I need some time to consider this. Do you need anything else right now?" 

"Am I staying in that room I was in downstairs?"

He glances at Nayoki. "If you prefer to? We also have actual guest rooms and you would be welcome to have one of those for now. And a library, if you like books. Sunspring could give you a tour of the facility if you wish." 

"I like books. And a tour seems like something I should do sooner or later."

:Nayoki, make sure you let her see books that would only contain the names of people who are dead now: Leareth tells her privately. This shouldn't be hard. Most of the books in his collection are more than a century old. Some of them have his previous incarnations' chosen-names on them, but if 'Leareth' didn't count, then neither will any of them; he thinks back quickly if any share syllables with his original body's name, but none were selected in any way related to that one. He asks one of his staff to go check now and remove any that are phonetically close, though, just in case. 

Nayoki also asks someone in private Mindspeech to go check the book index and remove any written more recently than a century ago, and then she can take Promise on a tour of the dining hall and show her the guest rooms and the public Work Room spaces (not the locked private offices or research setups.) 

Promise looks curiously at the human foods - so much of it does not look like food to her - and wants to know what the Work Rooms are for.

"For testing new forms of magic in! Some kinds of our magic explode if done wrong, or are dangerous in other ways, so it is customary to practice in shielded rooms."

Sunspring is also curious what fairy food looks like, if not like human food! 

"Well, it's all plants, and different ones. Fruits and nuts and leaves and roots and flowers and nectar and juice and such."

"Humans also eat all of those things! Those greens are leaves, carrots are roots... I suppose our foods are generally cooked and mixed together, so are less recognizable." 

"I'm used to eating most things raw. Sometimes I'd heat stuff up, or chill it, but not usually."

"I wonder why that is different! I suppose humans often get more nutrition from foods that are cooked, and also find them tastier. Is it inconvenient to light fires or use magic to heat things in Fairyland...?"

The library is now confirmed free of the names of any living people, and also of current royal families known to reuse the same names a lot for their descendants, so Sunspring can take her there.

Although she should check... "Promise, if you read a name in a book, and it is the name of a mortal who is long dead, but also is purely coincidentally the name of someone far from here you have never met, that is not the same as knowing their name and thus becoming their master, right? Humans in this world reuse names sometimes." 

"I don't know how I'd do it without magic and a lot of fairies don't bother learning sorcery so maybe all the plants have been cultivated to taste good raw," Promise says. And of the books, "Yes, I have to specifically entertain the hypothesis that a specific person's name is or contains a specific syllable before it will click."

"Ah. Good to know." Sunspring's blurred-out background Sight still lets her see that Promise is telling the truth here. 

She opens the door. "Well. This is our library." 

It's not that large, but the shelves contain thousands of books, discreetly shuffled a bit to make the spots where books were removed less obvious, and it has a couple of writing-desks and some cozy chairs by a fireplace. 

Promise scans titles, stepping slowly shelf to shelf. "This is a lot of books."

"Leareth is quite proud of his collection! Many of these ones are very rare, too, I think in some cases Leareth is the only one with copies." (Because he's Leareth, of course, everything here also has backup copies in various hidden records caches, which in general only he knows about.) 

"I've seen this many books in one place before but only once." She picks a book about magic.

Magic! 

In Velgarth, 'true magic' is often used as a term to refer to work done with mage-gift, and then there are the various more specific and single-purpose Gifts. Many places lump all of said Gifts together under 'mind-magic', even though some of them, like Fetching which moves or teleports objects, are really not very mind-related at all. 

The book gives a list of the specific Gifts, most of which are pretty self-explanatory from the name and also match the list discussed with her before, and then it dives into the many, many applications of mage-gift. Gates! The much rarer permanent Gates! Weather-magic! Heating and lighting and protective barrier-walls. Illusions. Detection wards. Shielding against all of the other Gifts. And, of course, a very long list of combat applications, starting simple with fireballs and levinbolts (this seems to just describe lightning as cast by mages) and moving on to various clever trap-spells, like ones that paralyze an enemy who steps on the trap. 

There's a sub-chapter on the summoning of extraplanar entities, which can be done by any mage above Master-level potential, but requires extensive specialized training to do skillfully. Elemental spirits from the four planes of Fire, Earth, Air or Water, and also Abyssal demons, can be given material-plane bodies constructed of mage-energies, which they control, and they bring some of their native magical abilities with them. Many air-spirits have an affinity for sensing minds and intent, for example, and fire elementals are very efficient at, well, starting fires. There's a kingdom in the far northwest of the continent that supposedly fuels its cookfires via mages making a contract with salamanders; they need to be paid in mage-energies, but on the ice and tundra, mage-energy is a lot cheaper than firewood. 

Combat use of demon-summoning is frowned upon in most of Velgarth, because the demons are indiscriminate about who they attack, and tend to cause high civilian casualties. The priesthood of Karse are known to have used this strategy anyway in their many wars of conquest over the centuries, and also to have passed off salamander-summonings as miraculous signs from their god, Vkandis Sunlord. 

Huh. She supposes they weren't expecting that to be Vkandis's real name.

She finishes the book anyway. When she's finished with this one she looks for one with more detail on the extraplanar entities.