The Caer itself resembles an old-earth castle, with heavy stone walls designed to keep the interior warm during the winter and cool in the summer. All of the rooms and corridors of the Caer are high and wide enough for the dragons to pass through. The Caer was built in two stages, with a small two-level part, and a larger three-story addition. The Caer is very very sturdy, and architecturally sound. The dragons often choose to lounge about in the sun atop the Caer, warming their hides, or cooling them in the breezes. The new part of the Caer boasts an exit on each level for the dragons, with heavy doors that open out onto sturdy balconies. Generally the use of these doors is avoided during the wintertime to avoid heat loss.

The hatching dunes are located in the middle of the older part of the Caer, on the ground level. It was planned this way from the outset, because the dragons are the heart of the Caer. The dunes can be exited to the second level by dragons and their bonds, but there are no stairs down from there. A ledge protects children from inadverantly walking into the dunes this way. The dunes are heated by hot springs, same as the Aerie's nesting cavern. Whether this spring is the same as the one at Ice High is beyond the telling of the folk of Belrin Isle, but they're happy that it is, no matter how it works. The spring provides water for the bathhouse, and for the Caer's (incredibly large) kitchen. These, as well as housing for visitors and bonders, and any dragon under a full year old are in the older half.

The rooms along the outer walls of the Caer are larger, and the inner rooms are generally smaller, though this is not always the case. Dragoners generally choose the outer rooms, with two dragons to a room, though they sometimes choose to live with their families outside the Caer. As long as every dragon reports to his or her fleet on time, it doesn't matter where they live.