Eternals were born from the energy of heaven and earth gathered by the gods. They could create vessels of power, but it required Kelsey's life force to awaken consciousness. Furthermore, the gods implant a tracking seed in every newborn Eternal.
The seed did not react if its bearer merely travels from place to place. However, if the bearer remains in the same location for one year, the seed will leave behind a unique trace of energy. If the bearer stays for two years, the seed would release a faint Eternal aura that can only be detected by other Eternals. And if the bearer remains in the same place for three years, the bearer's life-breath aura will linger there for a long time.
