Of all the alliances in the world, the Grand Alliance is perhaps unique in finding it so difficult to comprehend the nature of an alliance that they even need to name their meeting space the Unity Chamber just to remind themselves that they are, in fact, on the same side.
The Unity Chamber is a magically-created demiplane where the leaders of the Grand Alliance of Free Peoples can meet, plan stratagems, and air grievances. The Chamber is rather odd in nature: it consists of nothing more than a perfect hemisphere, around sixty feet across. The walls of the hemisphere are solid, jet-black walls of pure magic. Its floor is made of some light-grey grainy rock, perfectly smoothed into a single solid piece. The middle of the Chamber is dominated by a large table, made in a single piece from the same rock as the floor. More mundane cushioned wooden chairs, adjusted to be comfortable to the various member-species of the Alliance, are clearly a later addition. Around the edge of the Chamber are positioned fifteen stone doors, equally spaced from each other. The doors have no frames, but simply stand unsupported and unmoving. Indeed, they have no features to them at all, not even a handle, and they look superficially like no more than stone slabs standing upright. Despite this, something about them means that all who look upon them knows that they are doors.
The rulers of the Alliance nations can enter the Chamber through a matching door kept securely in their capitals, opening only to an amulet entrusted to each ruler. The Illuara are the ones who provided the doors and the amulets to the Alliance, offering it freely as a gift "for services rendered". Each amulet is keyed to a specific door, and only one person can use it to enter the Chamber. The rulers sometimes come in person, or other times send a representative. Meetings happen as required, either between all Alliance states or more commonly with just a few present.