Atla is George's twin brother. He wears the robes to conceal himself from scrying magic, which would casue all sorts of confusion over their being twins. He takes a more direct tack than George, aggressively trying to drive Terek Domar out of Ylelon. His leverage is that he has stolen Terek Domar's hoarde and hidden it with a "contingency plan," wherein it will be destroyed if anything happens to Atla. The only thing greater than Terek Domar's hatred of Atla (and George) is his avarice, so he cannot strike out against Atla.
Terek Domar came to Ylelon for its material weath, manipulating the people of the land into making it rich. It began a campaign of destruction against both the native people and the monsters of the land to make it more habitible for forigners more capable of extracting the mineral riches from the Sentinel Mountains.
Ylelon is infested with the supernatural because the wickedness of Terek Domar and its magical nature as a dragon draws them near. If Terek Domar can be defeated or driven out, Ylelon will beomce a much safer place for mortals.
Of course, none of this is true. Or all of it. Or tiny snippets are true. We'll just have to wait to find out. By "we", of course, I mean "all of you."



