Aeternitas (pronounced “ai-turn-it-ahs”) is a Roman goddess and the personification of eternity.
Aeternitas was symbolized by a phoenix or a worm/snake biting its own tale, forming a circle. She was also shown in human female form wearing the usual long gown of a Roman woman and holding a torch, globe, or scepter, or holding the heads of the sun (Sol) and moon (Luna).
Aeternitas doesn’t appear in any myths. As the concept and personification of eternity, she was often used by the Emperors to emphasize the eternity of the Empire, their rule, and to emphasize stability.
Light and Dark Side
Because Aeternitas is mainly the personification of a concept and not actually a goddess who appears in myths, she probably doesn’t necessarily have a Light or Dark side. On the upside, Aeternitas represents longevity, and suggests stability. On the downside, eternity isn’t always a good thing. A person doesn’t really want to live forever if they’re going to be alone and have to watch their loved ones die while they live on, for example. Nor would eternity necessarily be a good thing if there is a despotic or terrorist regime in power over people (though the regimes probably think it would be great).