Theory Time

Sooo..... From the recent dream the FL had, she use to be someone lived in that world. She lived a horrible life until she met someone who look like ML, which I believe to be the twin older brother god. They became very closed and maybe had already became lovers. Because of this, the younger twin sister goddess was jealous and killed the FL, and the fight between the creator gods which mentioned in legend, began. It said that the siblings got into deep slumber, but I think there's a possibility that they both died as a god and reborn as human and lost their memories. Meanwhile, the FL got reincarnated as a human female in a different world until she came back to the magical world. As to why she reincarnated on Earth before, that maybe the older twin brother god's doing.
That's it! It's just some wild imagination that suddenly came though.