The Chamber is a secret organization of Dragons, no more than a hundred, that attempt to manipulate events on Khorvaire. This is in direct contrast to the prevailing attitude of most dragons on Argonnessen, who are mostly obsessed with the Draconic Prophecy and not disrupting it.
The Chamber, while prone to taking an active hand in the affairs of Eberron, is not a body that works directly. Indeed, very few beings know of its existence. Instead, the Dragons of the Chamber operate through proxies in order to keep their involvement secret. But occasionally some of the dragons in the organization do take a direct approach and disguise themselves as one of the lesser races and offer their help as advisers to royalty or watching silently while manipulating from behind the scenes.