Copy and pasting what i say about The Story even on here so i don't have to remember if i posted thing x on website x or y.
Earth is a peripheral planet compared to the ones that are inhabited by celestial beings: it first got inhabited because of its favourable conditions but because of the distance from the main planets + the sheer amount of time it took to get to them, it slowly became more and more unpopular and the majority of the CB moved back to their original planets as it simply wasn't worth it.
Moving from one place of the galaxy to another is a big thing!! Only a specific type of celestial being is able to make that journey in a sustainable amount of time: light rays (the personification of, so Ester!).
Neither Lilith nor Phebe are light rays and have to rely on portals made by LRs to move from one planet to another (especially with planets that far away from each other): during the en masse exodus away from Earth, they erroneously got left behind and they ended up being stranded on Earth. They both tried to send messages through space in the hopes someone will be able to receive them, and come get them, but alas, to no success.
Phebe eventually accepts their condition and starts fully adapting to living on Earth and conducting a life there, but Lilith never lost hope and believes one day, she will be able to go back home.
Ester lost her memory and does not know that she's a Light Ray, and definitely doesn't know how to open portals, so let's say Lilith's hopes and dreams upon seeing her got shattered in a million tiny pieces