In Greek mythology, there were some gods and goddesses called "primordial deities." These were the very first gods who existed before anything else, when the world was just a big, empty space. They were not like humans or animals, but they were like powerful forces that controlled the world.
Some of these deities were the personifications of natural phenomena, like Chaos (which was the empty void that existed before everything), Gaia (which was the spirit of the earth), and Ouranos (which was the personification of the sky). These were very important because they controlled all of nature and the elements.
Other deities were the personifications of emotions or concepts, like Eros (which was love) and Nyx (which was the darkness of night). These deities were important because they represented things that humans feel and experience.
Overall, the Greek primordial deities were like the creators of the world, and they controlled everything that happened within it. They were worshipped and revered by the ancient Greeks who believed that these deities had the power to protect and help them.