I tried to make sense of Abaddon: Princess of Decay lore

I couldn't find any topic on that matter and since this game has a very interesting story but it's pretty hard to patch it all together, here's what I understood, written down in this post:

https://www.reddit.com/r/visualnovels/comments/uh37mb/trying_to_piece_the_lore_of_abaddon_princess_of/