A/N: Nope, not a member of the Organization or even Vanitas either.
You know, it's kinda interesting to see just how easy it is to hide the identity of the black dragon - after all, anyone who's played Kingdom Hearts 1 has seen it. That might give it away actually, but I figure it's about time I gave you some clue.

The rucksack was thrown into a nearby chair, the skateboard kicked into the room and the door shoved closed seemingly all in one fluid motion, then he leaned against it, staring at the floor. Now the fear was starting to pass, he was starting to think clearer.
"Roxas? You look like you've seen a ghost, what happened?"
It was Naminé, of course. He looked up to her, took a few breaths to compose himself, then answered, "Not a ghost. Dragon. It was staring at me."
"The dragon." She said slowly, not quite believing him. He nodded. "The dragon was staring at you."
"It was on the roof when I left my home."
"Roxas, you were meant to be going to the library."
"Gone," he shook his head. "It got burnt down. Had to break into the official library."
"Are you nuts?" her voice soared, making him wince. "Do you have any idea what they'll do if they find out?"
"Not half as much as if they find out I stole a book from there." Then as if to try to placate her he added, "I brought lights – proper lights so you won't have to put up with the smoke."
"Roxas, this is not the time to be talking about the lights!"
"Better than talking about dragons," he pointed out, then retrieved the book, along with everything else he'd brought along. "This was the only one that said anything about dragons in the title."
"Hold on there. Before you get stuck in there, I want to know what you got up to."
He sighed, realising he wasn't getting out of this, then mentally condensed it down.
"I left you here, found a red dragon underneath Dragonbarrow, found the library burnt down, went to the official one, got this, went home to pick up some more things, left, saw the black dragon on the roof staring at me and came here. That's it."
"There's another dragon?"
"I don't think it's much of a threat. It looked pretty weak to me." He frowned, recalling the eye and the unusual questioning sound it had made, then added, "I think there's something more to that one as well. Something about it seemed kinda familiar."
"We can deal with that one after the one menacing the town."
"I don't know... maybe we should help it. The red one I mean."
"Help a dragon. You want to help a dragon."
"Yeah. Why?"
"Roxas, has it occurred to you that once it got up to health again, it might just turn on us? Dragons aren't trustworthy, we're told that all the time."
"I'm not convinced, and won't be until that book says anything to prove it," he disagreed. "They at least seem like intelligent creatures to me. I'm pretty sure it wouldn't turn on anyone who helped it, and if I'm that one, maybe I can convince it to help..." he trailed off, an idea forming. His eyes strayed thoughtfully to the book in hand. "Well now," he murmured beatifically. "Isn't that an interesting thought?"
"I can't believe you," Naminé burst out in exasperation. "First you want to take on one dragon, then you want to help another, and now you're planning to use it to do who knows what now?"
"Ask," he corrected, "Not use. Ask. I'm pretty sure if we help it, it'll be willing to help us in return, maybe even with the other dragon."
"You don't know that it'll do that. For all you know, it could side with the other dragon, and we'd end up paying two sacrifices instead of one!" Naminé shook her head, then continued, "Just drop it, Roxas. If you find something that can help with the first one, you should pass it on to one of the senators; they'll be able to put it past the senate, and they'll decide if it's worth it or not."
"How do we know they haven't already done just that?" he argued. "How do we know the entire reason this book was in their library was because they didn't want people like me to find out that just anyone could deal with it?"
"It's too dangerous!"
"I'm willing to take the risks if it means being rid of the monthly sacrifice. Even if it means helping the weaker dragon. Are you with me?"
"Absolutely not! I think you've gone completely insane."
"Maybe I have," he shrugged. "But I'm going to do it all the same, whether you're going to help or not."
Naminé shook her head again, then took the lights he'd brought along, muttering to herself as she figured out how best to light the hideout with then. Roxas moved a chair nearer to a torch, opened the book to the contents, looking through the chapter headings.
It listed:

Contents

About the authors … i
Preface … iv
Chapter I – A History of Dragonkind … 3
Chapter II – The Noble Dragon … 168
Chapter III – The Wyrms … 205
Chapter IV – The Wyverns … 249
Chapter V – Colourations and their Significance … 389
Chapter VI – The Dragonkin … 444
Chapter VII – On Dealings with Dragons … 487
Chapter VIII – Notable Dragons and Dragonkin … 521
Chapter IX – Humans through the Eyes of the Dragons … 560
Chapter X – The Draconic Language … 602
Chapter XI – Closing Notes … 656

So there was more than one kind of dragon. Were these 'Dragonkin' dragons too? Being separated from the other three chapters suggested they weren't. Either way, it looked like this was going to take longer than he'd first thought.
Maybe he'd get better answers direct from a dragon, but there was only one dragon that might consider talking to him – and if this book was anything to go by, he'd need to learn their language before he could understand them.
A cursory glance into the opening lines of that chapter said that all kinds of dragons had their own dialect of Draconic, and that if he were thinking of attempting to speak with any, he'd need to know what kind they were. Noble Dragons never deigned to speak the other tongues, while Wyverns spoke all. Wyrms knew the Noble and Wyrm dialects only, and considered being addressed in Wyvern an insult. It seemed obvious that for best results, addressing them in their own tongue was the best course.
Knowing their history didn't seem like it was going to do him much good, and at over a hundred and sixty pages, easily the largest chapter of the book, he wasn't going to delve into it unless it became necessary.
He was going to have to read through the chapters on the specific kinds of dragon to see which ones he had to deal with here, so opened it to the Noble Dragon, and started to read.

The Noble Dragon, easily the most majestic of dragonkind, are so named for their temperamental resemblance to noblemen in feudal systems; territorial, proud, arrogant and quick to lash out at those who cause offence. They consider few actions as beneath them, though like such noblemen are not above manipulating others into doing their bidding.
Noble Dragons see all other creatures as but servants, and other dragonkind as threats. They hold respect only for the great Wyrms, though only due to their immense resistances to the Noble Dragon's capabilities. Wyverns on the other hand are considered as an insult just allow in their territory, and will be set upon without hesitation. Other Noble Dragons are oft regarded similarly, as their territorial nature gives nothing for cooperation or even getting along. Only the mating season offers any respite to this, but the males are known to ignore it unless a female selects him to father her offspring.
When identifying a Noble Dragon, there is one criterion that no other kind possesses; forearms not attached to the wings. These front arms, though the appendages upon them more closely resemble the feet, are as dexterous as human hands, though far more powerful and swifter. These dragons also stand considerably taller than their Wyvern cousins, being the largest of all dragons.

That sounded like an almost perfect description of the dragon terrorising the town. One dragon identified, one left to go.
He flicked through the remaining pages on the Noble Dragon, only scanning the text for anything that stuck out about them. There was little of note though, only a few pages describing their unusually limited abilities.
The next chapter was on Wyrms. Almost as soon as he began to read, it became apparent that the red dragon was not a Wyrm at all, but it offered some interesting suggestions.

The great Wyrms are the only kind of dragon that is landbound, possessing no wings to fly with. These dragons are seldom seen, and are highly antagonistic, even more aggressive than the Noble Dragons, but as most of their time is spent out of sight of others, these traits are seldom noticed.
Wyrms prefer the dark depths of the land to the open skies, leaving great tunnels behind them as they carve their way through the landscape. As their primary diet consists of various metals, miners often risk their lives to follow Wyrm tunnels in the hopes of finding a seam that it had ignored. This carries the additional risk that some Wyrms double-back to consume such seams later. Coupled with their incredible sense of smell and sight in the dark, escape from a Wyrm attack is highly unlikely.
Some Wyrms have however been known to differ from this temperament when a Dragonkin has been present, frequently coming to mutually beneficial agreements whereby it gains the sustenance it requires, and in return allows other humans to mine the metals they ask for. Such agreements are often short lived though, as the Wyrm will eventually move on to find other grounds to feed.
Wyrms are highly dependable and honourable, and even if they move on, they will never break an agreement made, whether with human or Dragonkin. Some few have even been known to respect agreements made with other Wyrms, though one should not depend upon this.

The tunnels underneath Dragonbarrow... they'd been there when the town had first been formed. They'd added the tunnels that connected it to the outside world, and added caverns near the surface for them to use, but the actual tunnels had always been there.
There were no tool marks on the walls either. They were almost universally rounded, with a flat bottom to them. It seemed likely that a Wyrm had passed through and created the tunnels, but it also seemed unlikely that it was still around.
That just left the Wyvern. That last dragon had to be a Wyvern, and so after another cursory glance through the pages, he flicked forward to the Wyvern's chapter.

The Wyvern, often considered not to be of the dragons, are the most numerous kind, and have the best record of dealings with humans. They are smaller than the Noble Dragon, lacking the forearms and much of the power, but they make up for this with improved agility in the air and far better manoeuvrability.
Perhaps most unique about the Wyverns is that any kind of dragon may produce them, as any unfertilized egg may hatch into a Wyvern. The chances of this happening are not high, but as most Wyrms and Noble Dragons lay many eggs, enough of them survive to ensure the continuation of the Wyverns.
Wyverns are also known to be the only kind of dragon that speaks and understands all three of the Draconic tongues without issue, something neither Wyrm nor Noble Dragon holds close. They alone hold themselves above petty distinctions, and despite the ill-regard they garner in both of their cousins, they still attempt to get along with them.
The most notable trait of Wyverns however lies in the Dragonkin. While Dragonkin naturally hold special regard and in some cases power when it comes to any kind of Dragon, when a Wyvern accepts a Dragonkin as his partner they both gain much from it. The Wyvern becomes empowered, sometimes even enough to take on Noble Dragon, and the Dragonkin may partake of certain traits of the Dragonkind, usually chosen and dependant on the colouration of their partner Wyvern.

A Wyvern. The red dragon was a Wyvern. The weakened condition was explained too now – it had run afoul of either the Wyrm that had created the tunnels, or the Noble Dragon outside. And if what he'd read was accurate, he stood more of a chance getting it to talk to him then he did the Noble Dragon.
All he had to do now was figure out how to help it and how to talk about it – though curiosity pointed out that perhaps finding out about these 'Dragonkin' was a good idea too... especially given the connections it had mentioned.