Humans and their cosmic neighbors share striking similarities. The two species share almost identical physiological structures, similar thought processes and perceptions and even lack reproductive isolation. This similarity allows the Nox to easily communicate with Earthlings and directly utilize Earth's industrial products. Outwardly, the most significant difference between the Nox and Earthlings is their distinctively shaped ears. However, the most substantial difference lies in their EGO abilities.

EGO is a supernatural ability unique to Ruvilian women, spontaneously manifested under the influence of strong emotions. EGO exhibits different effects depending on the user's emotions, including but not limited to: enhancing limbs, controlling external temperature, manipulating fluids, special perception, interfering with the minds of others and healing. However, most people possess negligible EGO abilities, so the status of women in pre-revolutionary Ruvilian society did not generally improve. Only a few exceptionally gifted or meticulously trained individuals possessed relatively practical EGO, enabling them to rise to the elite class. Because the Talab Order, which inherited EGO practices, was banned by the Republic for supporting the monarchy, it has become extremely difficult for contemporary Ruvilian people to access traditional EGO techniques.

Clearly, EGO exhibits typical X-linked recessive inheritance characteristics. The Nox Genome Project, launched in 1992, aimed to sequence all the genes of the Nox people to decipher their genetic information and finding the "EGO gene" was naturally a key objective of this project. However, after the end of the space race, the Nox Genome Project has faced difficulties due to insufficient funding and therefore, fully unveiling the mystery of EGO will still take time.