From the introduction:
Welcome to the three Realms of Terrille, Kaeleer, and Hell. This is a world of mystery, passion, violence, and ritual, ruled by the Queens of the Blood.
Each Realm is split into many Territories, which are further split into Provinces, which are then split into Districts. Each District, Province, and Territory is ruled by a Queen and her court, made up of the males of the Blood.
The Blood are those who possess the power of the Jewels, and are split into castes by their inherent nature. A Queen is meant to rule and gather a Court around her in order to do so, while a Healer is meant to mend the wounds of others.