The covenant of Mac Gruagach is part of the larger Clan Mac Gruagach (the children of the son of the wizard). Calum Mac Lachlan, a 135-year-old gruagach, is the real head of the covenant. The aim of Calum is to integrate the ancient lore of the gruagachan with that of the Hermetic Order. To this end he has sent a number of magi to other covenants. For example, he sent Domnhull Beg to Durenmar, the domus magna of House Bonisagus. Calum and Aonghus Lamh Iarran are both officers of Clan Mac Gruagach and must ultimately follow the commands of Donncadh Mac Calum, who is the chief of the clan.
The covenant is organized along the lines of a typical Highland clan, and the covenant buildings are spread throughout Glen Glas, rather than huddled close together. Much of the valley has a Magic aura, which ranges from 0 to 5. Each member of the covenant builds his or her residence on a site that suits his or her magic, with Domnhull living on the only site with an aura of 5. Each house has its own Aegis of the Hearth, as the entire glen is too large for one Aegis. In the hills surrounding the covenant are shielings for the summer cattle herding, as well as the houses of the more reclusive members of the clan.