Earth was inhabited first by The 12 Families Ancestors, but among the 12 there were Divine Demi-Gods that didn't even know they were Half-Gods and Pure Human Candidates that survived the process of Natural Selection during their creation, they just thought that everyone was human and so they are together one as humanity.
The Families don't have a hierarchy during their time in the Era of Creation and Birth, this was what lead to the unity and non dividance of the families that made them exist and evolve through centuries together.
The Ancestors lived long before the existing knowledge of humans being suitable for the evolution of the gods, and even long before taking the first step on the mountains that lay between the horizon and the end of the observable world.
During the beginnings of humanity they believed that the gods were the higher more omnipotent beings, they hail them someone like Barbatos, as an all powerful being capable of doing impossible things. The human ancestors respected the gods, for they know that they were not created without the help of another divine being.
The 12 Families lived for survival and advanced throughout time, each with their own goals they exist to pierce through the norms of the strong, even though they don't step on top of the food chain, and even if they are tiny little beings, they break the boundaries of what makes a human weak through evolution, technology, and knowledge. These seemingly not so powerful things became the sole holder of their position above all other creature with that reason.
The 12 Families, Rhethia, Lianca, Arcea, Viraneus, Trifpheld, Anccarra, Valentine, Gallennia, Meyrande, Dolte,
Kusha, and Recillia. These Families were the first and serve as the ancestors of humans. Barbatos each created a goal to suit a need for humanity as a whole, each leading their lives with that goal in mind. Other than the goal for a greater humanity, each of them also had an interest they want to achieve because it was in their interest and it seems as a way to walk into the road to the betterment of humanity.
These became the source of knowledge and experience, along with countless battles and tribulations. Through these hardships sprouted knowledge about what the world around them was. The making of The Book of Creation, The Map on the World, The Red Chronicle, and The Ankh. These works of literature became the source of knowledge that lead to the power of humanity, through milleanias it served as a catalyst to create this idea that the humans need to become stronger for their own good and for the continued existence of humanity.