The Campaign Builder's Guild

You have here the potential for a very nice high-magic setting.  Normally, I don't care for those, but your setting caught my eye.  The following questions are more food for thought for you, rather than things you are obligated to answer.  Note that this is written stream of consciousness, so I might ask some questions that I find out the answers to by just reading on more, but I think all the questions are still valid.

Races in Derunas:
So you have a list of races here, which is all well and good.  It lets players and people like myself see the options available in this campaign.  However, I think there are some things that you could do to improve it.

You might want to go over if any of the races differ from how they are presented in their relevant sources, in this case either the Player's Handbook or the Monster Manual.  Do humans only have one ethno-linguistic group (i.e. do they all look the same and talk the same)?  Or do they have several ethno-linguistic groups?  The same applies for other races as well.

You list "Elves (all kinds)."  It would probably be better to list these out, since, if I recall correctly, there are other elves not only listed in the Monster Manual, but also in other books as well.

Going along the first two questions, which subraces of gnomes, halflings, and dwarves are you using?  The ones from the Player's Handbook, or ones from somewhere else?

A Question of Class:
It might be a good idea to briefly list
Why are ninjas, something traditionally limited to Japanese culture, included in Derunas?  Why are samurai, like the ninja, which are normally found only in Japanese culture, included in Derunas?  The answer to this will be a lot clearer to me if you start to define some of the cultures.

Rune Knights are an interesting class, but what role do they serve?  Are they specific to one race or kingdom, or are they a worldwide thing?  The write-up on Wizard's site seems to indicate that they organize into orders.  Do they follow this in Derunas, or are they all self-taught?

The Setting:
You establish here that the setting is high magic.  You also establish a pseudo-post-apocalypse theme as well, in that the world is recovering from some cataclysmic event.  One thing that struck me right away was that you said the cataclysmic event was "unknown to [Derunas'] inhabitants," but don't really expand much on this.  Mystery is a good thing for an adventure, but as much of a good thing for a campaign setting as a whole, as it leaves gaps in the verisimilitude of the setting.

So, I have two main questions about this event. The first is, how long ago did this cataclysm occur?  There is no definition of time really given, aside from the implied before-present.  Was it couple of generations ago, and no one remembers for some magical reason?  Did it mark the start of your dating system (i.e. nearly 800 years ago)?  I think you could definitely state how long ago this cataclysmic event occurred without betraying its secret, if you were planning on keeping it secret, of course.

The second question is, assuming you're not trying to keep this secret, what was this cataclysm?  Was it some kind of magical disaster, like a arrogant arch-mage trying to steal the divine power of the deity of magic, and it backfiring when he is simply overwhelmed and magic in the world begins to collapse because the deity no longer can wield full control over it?  Or perhaps a wrathful deity decided to teach mortals a lesson, as it were, and partially wiped them out?  Was it a natural disaster of some kind, like a supervolcanic eruption that blocked out the Sun?  Or maybe a meteor or comet impact?  Was it something else entirely?  Defining what happened here will help to set the tone for the rest of the setting, in that it can show what kind of feel you want for the setting: highly magical in the arcane sense, highly magical in the divine sense, highly psionic, dark and gritty towards players, etc.

Next, you mention a "deadly war" involving the various races in Derunas.  So, when did this war start?  Has it been relatively quick, but massively bloody?  Has it been raging on for decades?  Centuries?  Also, if it is either written down or still in recent memory, how did this war start?  Did simple border conflicts evolve into something bigger?  Did racial hatred motivate one side to attack first?  

The aforementioned cataclysm and war, when combined, seem to point towards a gritty feel.  If that's what you're going for, expansions in both of these events will really help push the theme on players and readers.  If that's not what you're really going for, expansions on these and other areas could help as well.  Maybe the war is only confined to one small area, so that most people treat it like most people in modern first world countries do, that war is something far away you only hear about indirectly.

The information on the treaty that is mentioned should be kept relatively sparse, because it could make for a bunch of adventure hooks.

The Xuriam:
My only real problem here is that you're keeping some information a little too secret, but then again, it may just be the way in which you wrote this up.  You mention things about the cataclysm here, but not in the beginning; while I have no problem with this, the beginning is just so vague about the cataclysm, if you skipped this section, you'd never find out about it.

Again, a few questions come to mind: what was this cataclysm?  Since you've established that the Xuriam don't remember why they did it, why don't they remember?

This section suffers from some coherence issues.  I'd suggest that you go over it again.

The Aasimar:
You mention here the leShay, and that a catastrophe happened to their world eons ago.  Is this a completely different world than the one so far described?  Or is it something else?  Also, you mention the cataclysm again, stating that it wiped out a large number of the aasimar.  However, you don't get into any details.

Again, there are some coherence issues here.  Look it over again.

The Tieflings:
You mention some brief points here; nothing much to comment about.  If anything, this section is taken too much from a Xuriam point of view, and really doesn't provide anything substantial to the reader.

The Kingdoms of Today:
There is a brief description of the history of the war, but not much else.  Perhaps you should move the war to its own section, and focus on the kingdoms themselves?

The Draconic Empire:
Not much to comment on, as there isn't that much material.  This, like all the other sections, has potential, it just needs some work.

General Comments:
All in all, I think you could do several general things, in addition to what I listed above, to make this work a little better.  My first suggestion, really more of a nitpick, would be to go back and check for spelling, as there are a couple of errors here and there.  

My second suggestion would be to do a bit of organization.  Right now, there's a lot of information on the current war and the cataclysm of old, but it's all scattered around, and you basically have to read everything right now to get through it (notice how my review asks some questions that get answered later on, I commented as I read through.)  One of the biggest improvements through organization you could do right now would be to make a "Races of Derunas" and a "History of Derunas" section, and merge relevant information into these.  That would help make most of this a lot more coherent.

Finally, you might want to look over this set of questions.  I've found it to be a good spring-board for getting the creative juices flowing, when it comes to world design.

Thanky you for the questions, limetom, i will have many things to ponder now, but instead of pondering, i give you:

 [spoiler Gnolles] The Gnoll empire is feudal, and the gnolls are much like the ancient Japanese. They hold honor above life, and believe in a pantheon of gods. they are not at all like the gnolls described in the MM. They are a highly organized, and respectful people (as long as you show them respect). More to come later.[/spoiler]

And now for some other various answers:

The year system is based as 0 being the catastrophe.

I am not at liberty to divulge what the catastrophe is, it may be revealed at a later time...you'll just have to wait and see.

Elf kinds:
Sun Elves (regular elves)
High/Gray Elves (called high elves by other races/sub-races)
Deep Elves (Like the drow in ways, but not quite as sadistic)
Sky Elves (They are slightly more technologically advanced, they have skyships, etc. and live in skycities)
Wood Elves (Less regal and more feral variety)
Desert Elves ( The wood elves of the desert)
I will expand on Sky and Desert elves later on.

The rest will have to wait. Vanguard:Saga of Heroes beckons me.