P208:6, 18:2.1 Each of the billion worlds of Havona is directed by a Supreme Trinity Personality. These rulers are known as the Eternals of Days, and they number exactly one billion, one for each of the Havona spheres. They are the offspring of the Paradise Trinity, but like the Secrets of Supremacy there are no records of their origin. Forever have these two groups of all-wise fathers ruled their exquisite worlds of the Paradise-Havona system, and they function without rotation or reassignment.
P208:7, 18:2.2 The Eternals of Days are visible to all will creatures dwelling in their domains. They preside over the regular planetary conclaves. Periodically, and by rotation, they visit the headquarters spheres of the seven superuniverses. They are close of kin to, and are the divine equals of, the Ancients of Days, who preside over the destinies of the seven supergovernments. When an Eternal of Days is absent from his sphere, his world is directed by a Trinity Teacher Son.
P209:1, 18:2.3 Except for the established orders of life, such as the Havona natives and other living creatures of the central universe, the resident Eternals of Days have developed their respective spheres entirely in accordance with their own personal ideas and ideals. They visit each other's planets, but they do not copy or imitate; they are always and wholly original.
P209:2, 18:2.4 The architecture, natural embellishment, morontia structures, and spirit creations are exclusive and unique on each sphere. Every world is a place of everlasting beauty and is wholly unlike any other world in the central universe. And you will each spend a longer or shorter time on each of these unique and thrilling spheres on your way inward through Havona to Paradise. It is natural, on your world, to speak of Paradise as upward, but it would be more correct to refer to the divine goal of ascension as inward.