The Horrors are things that make even Great Dragons go, "Frag this for a game of soldiers, I'm outta here!". They come when the Mana is at it's highest point, kill (Or make those they don't kill envy the dead) everything, and this time, they're coming early!
This has all the Immortal Elves (Who built the Tir countries and taught Elves their "Ancient Culture and Language" with a lot of Celtic theft from the corruption that happened during the Fifth World) and Great Dragons (Who slept through the time of low mana, but were hunted down and are far lesser in number. One almost woke up from Tunguska, but "The Laughing Man" apologized for that.) from the Fourth World (The last time magic was around) looking at all their plans they made and go, "Aw... DREK!!!"
Ghostwalker hates the Azzies because some of their work is decreasing the time it'll take for The Horrors to come over even further. He smells their magic upon them, and is not a happy dragon. There's also the fact that he woke up late and the rest of the Great Dragons went, "Uh, yeah, dude, sorry about your Brother, man."