Pentworth's Dissection and Findings on the Dragon Corpse
From the official report of Dr. John Pentworth, head artifact researcher for the Vault.
The beast is massive – likely seventy feet from tip of head to tip of tail (impossible to tell, as the two are no longer attached, and far too much tissue has rotted off.) Most of the tissue is inflicted with enhanced stages of necrosis consistent with the effects of advanced (albeit very sloppy) Necromantic Magic. The wings have entirely disintegrated, barring the very most vestigial remnants. Despite the rampant decay, the scales on everything but the neck and underbelly are as incredibly resillient as dragon scales have ever been described to be. (Please Mr. Underwood, if you read this, reconsider my request to build a suit of armor out of the scales!)
Origin of the beast is difficult to discern at this time – to judge from the necrosis, this creature has been dead for at least three hundred years, and reanimated for most of that time. It seems likely that it was brought into the cathedral through an infernal summoning spell, much like the Ninebearers. The unpleasant implication, of course, is that it had been stored in some Netherworld until the Nine within Nine needed it. Unfortunately, I have been as yet unable to discern anything more precise than this due to the (frankly unacceptable) time it took to get the cadaver secured within the Vault.
That said, it seems obvious the Nine Within Nine have at least one very skilled necromancer and possibly a portal master as well – someone able to resurrect a creature like this at all would have skill that, I hate to admit, dwarfs even mine (at present, anyway). Of course, that was three hundred years ago, which would remove any type of mage but a necromancer from our list of concerns altogether. Unfortunately, a necromancer with a few hundred years more under his (or her, must be eglatarian) belt tends to only be more dangerous…