Librarywards indeed.  This particular library divides its books into "narrative" and "reference" rather than fiction and nonfiction, and further subdivides "narrative" into "bright" and "macabre" rather than any familiar genres.  The "reference" section contains mostly histories of Tairil, books on battle tactics geared toward small groups of powerful individuals fighting enormous monsters or armies of smaller monsters, and textbooks on magic.

Battle tactics seem most useful.

Versus big dragons: attack rapidly and frequently.  Coordinate attack patterns beforehand with your squadmates.  Unless you're facing something called an Amphithere, you're probably faster in the air than your opponent; it's often better to dodge than to block.  (All the guides seem to assume their readers can levitate and zoom around in the air pretty much however they want.)  The fact that you will reincarnate if you die does not mean death is tactically insignificant; take steps to protect your life.  Follow your squad leader's orders, because it's more important to act as as a coordinated unit than to implement every possible good idea.

Against "most varieties" of dragons, destruction of the brain "or brains" of a dragon will kill it, but they don't seem to strictly speaking need any of their other organs.  Hydras, apparently, can survive without any heads.

Dragons seem to come in varieties, which tactical manuals assume the reader is already familiar with.  He can discern a few details by implication, though.  Wyverns, the kind he fought, are most similar to folkloric dragons, with two legs instead of four.  Hydras seem to heal a lot better than other dragons, and can grow extra heads.  Amphitheres are faster, and, by implication, might not have limbs.  Salamanders' actual bodies are comparatively minuscule, and are usually surrounded by nonspecific environmental hazards, the sorts of things that Wyverns might exhale.  Wyrms are rare, enormous, and dangerous.

And all these names are translating to things he already knows so this is helpful. He memorises this to ask questions later.

After a time, a tiny, vaguely squirrel-like root creature scrambles up the bookshelves next to him and proffers a small, rolled-up piece of paper.

He accepts it with a "thank you."

The creature scurries away.

The note says:

Sadde - 

i read over Eleanora's notes.  i'm ready to talk shop whenever you are.

...with directions from the library to Zacharias's lab.  It's signed "Rias."

To the lab he goes.

The lab, as near as he can tell, is near the center of the facility.  Sadde enters onto an elevated walkway above a chamber containing an array of coconuts the size of small rooms, suspended a few feet above the ground by thick vines.  Against the opposite walls are tables strewn with piles of notes, leaves, bowls of what look like deep-fried crickets, and a few small stone birdbaths.  Someone, presumably Zacharias, is hunched over one birdbath.

He looks up when Sadde enters, and claps his hands.  "Aha!  Sadde!  You're Sadde, right?  Am I saying that right?"

"I am, and you are. It is a pleasure to meet you." He walks over to Zacharias.

"Yeah, you too.  Salted cricket?  No, you don't eat, right.  So, I hear you can do lotsa magic really fast."

"That's a way to put it. Should I give you the full explanation instead of assuming you already have it?"

"Nah, I think I'm caught up.  Lemme see..." he grabs a sheaf of papers and starts leafing through them.  "Aha.  Conjuring biological substances.  So, here's the deal.  Big dragons, wyverns and hydras and salamanders and whatever, Sky Knights handle those.  But even with Azimuth there's not enough of them to effectively fight off the swarms of lindworms that come along too, so we have our plant monsters and our normal militia stationed around the Brush to take care of those.  And Sky Knight weapons are magic as fuck, so they can break open a dragon's skin or bone or whatever, but we can't hand out Sky Knight weapons to every conscript.  So what we have to do instead is use Wellsprings to grow trees that have magically durable wood, and turn that into weapons, and our output is bottlenecked by how fast we can develop and grow magic trees.  Plus we can't test them effectively because we don't have any draconic tissue samples.  So where you come in is, I'm hoping you can conjure up our magic woods faster than we can grow them, or possibly something better - vampire bone's supposed to be really durable, right? - and also make some dragon skin and dragon bone to test out our weapons on, so we can start experimenting more to make more interesting things than pointy sticks.  So, that's project A of several, with me so far?"

He speaks very quickly.

For a human.

"Yes, that sounds reasonable."

"Now, what I know for a fact Eleanora's gonna want to do," he says, "is turn as many militia members as possible into vampires.  And on the drinking-blood front, what I'm gonna try to do is cook up something that you guys can eat that'll work as well or better than animal blood.  I'll need to put a sample of vampire venom into this guy," he taps the nearest birdbath, "and do some analytics, but I don't need you for that except for the actual sample."

"And number three," he continues, "and this is the big moneymaker, is I want us to work out a ritual to purify corrupted Wellsprings.  I don't know how much you know about dragon blood, but it's dangerous stuff, and if it gets into a Wellspring it hijacks it and makes it start pumping out lindworms.  In theory, Wellsprings are self-purifying, but on their own they can't filter out dragon blood.  As far as we know, every Wellspring outside the Polity is full of dragon blood and useless to us.  If we had a way to purify them, we could push back against the dragons, start retaking territory instead of just defending what we have.  But we haven't had any luck at making something better at purifying than Wellsprings already are.  It should be possible in principle if I could retool a whole Wellspring to work just on that, but something based on sorcery would probably be easier."

He nods along. "I should perhaps create a new sorcery school, then. The one I made is purposefully bad at cleaning things for, ah, historical reasons related to why I invented it in the first place. It can be done, it's just much less efficient than everything else."

"Gotcha.  So, that's what I thought of looking at your magic versus ours.  I can give you a better rundown of what we can do than whatever whoever you've talked to gave you, and you can see if you come up with anything else."

"Yes please, that sounds like a good idea."

"Okay!  So the big ticket item here is Wellsprings.  Magic self-purifying lakes.  Technicians, people like me, meditate on Wellsprings - aah, basically sit down next to them and try really hard to notice the magic radiating off them, and then notice the shape of the magic radiating off of them, and the patterns it's arranged in.  Wellsprings radiate their magic into the plants around them, for like miles and miles around, and turn them into friendly magic plants.  Like, their fruit is really good for you or they heal a particular disease or something.  But when you meditate on a Wellspring, you can change the patterns of magic encoded inside it into other, more complicated patterns, that they don't know how to make themselves, or that it wouldn't occur to them to try to figure out.  - I'm talking about them like they're people, and in some ways modeling them as being like people is a good approximation, but meditating on a Wellspring isn't really like communicating with another person."

"So, you can meditate on a Wellspring and look at the patterns it has, and once you've done that to a bunch of Wellsprings you start to get a feel for what patterns get what effects, and then you can start sculpting your own patterns in the Wellsprings you meditate on.  Like, you tell a Wellspring, 'I want something that'll magically heal wounds,' or 'I want something that's as hard and easy to sculpt as steel,' or 'I want something that'll follow me around and carry my luggage for me' or whatever.  You have to figure out a way to translate that kind of instruction into the kind of magical patterns that Wellsprings know how to interpret, and then you feed those patterns into the Wellspring you're looking at.  And then, your Wellspring will either reject them out of hand, or else it'll take your patterns and kind of metabolize them, cut them up and shuffle them around and turn them into something it can do something cool with."

"And then there's more ways after that that the whole process is long and involved and complicated, but I'm getting off track.  The things that Wellsprings are generally really good at are - well, you've been in the cities, you've seen how everything is made of plants?  Tell a Wellspring to make some trees grow into the shape of buildings, it'll do that no problem.  Tell a Wellspring to make something that walks around and does stuff for you, that's easy too.  If you can make something out of a physical magical plant, that isn't too out there for a plant to do, you can tell a Wellspring to make it happen.  You can make things that affect the bodies of the people who eat them really well - like, heal wounds or cure diseases or put you in the 90th percentile of physical fitness or mess around with secondary sex characteristics.  You can make some kinds of magical substances, as long as they're vegetable in origin.  Stuff you can't do is like - you couldn't make a plant that made you telepathic, or gave you pyrokinesis; you couldn't make Gates out of magic plants; you can't really make, like... the stuff you make has to be magically biological, or magically chemical.  I don't know how much sense that makes to someone who doesn't do this for a living.  With me so far?"

"Yes. What's the biggest bottleneck in crafting magical effects with Wellsprings and is it possible to cheat at it by being the sort of thing that can run faster than sound and whose thought processes have been accelerated to match plus having perfect recall?"

"The big bottleneck is number of Wellsprings, since you can only fit so much into one, plus farmland for growing the magic plants, and I don't think there's much vampirism can do for us on that front.  But being a vampire would probably make it easier to get good at Wellspring hacking, plus if you've got perfect recall it's a lot easier to move patterns from one Wellspring to another, so you could probably grease some wheels going from R&D to production.  Uh... if enough people get vamp'ed it'll free up Wellspring real estate that'd otherwise be used for keeping people alive or healthy.  But nothing major is jumping out at me, I'm more interested in vampirism for the military and biokinesis for production and experimenting."

"Has there been much reproduction going on lately?"

He snaps his fingers.  "Right, vampires can't breed.  Ah - the Polity's getting close to hitting saturation, they've instituted population controls recently, and everyone's gotten really into The Civil Duty To Not Overstretch The Nation's Resources.  It's more popular out by the Brush, where people still die sometimes."

"I mean, vampires can in fact breed—vampire sperm still works on human eggs, but the human will typically die if not turned into a vampire immediately upon giving birth, and it's nonlethal for hybrids to carry—it sounds like it may be a good idea in the long term to slowly replace your human population with various levels of hybrid."

"I like the way you think.  Although come to think of it I don't know if all our berries will affect hybrids or vampires the way they affect humans, which could cause friction - you can't be turned into a hybrid so we can't make sure the first few trials consent to being guinea pigs - uh, I don't suppose you could - biokinesize - a headless but otherwise functional hybrid body to experiment on?  Or vampire body?"