Spoiler
In fact this word exist just because of her when she was little she dreamed of a world just for her and it was create later she will return to her "real world" and discover a 2nd novel with her actual life.....all is her creation....
Well its a litlle more complicated but I'll neef something like hours to explain lol but if you want ill try.....
Well I will tell you all the story even the real ennemy since it's the story complete children who suffers can create their own world so since little real Aerin has create this world all in this world and in the same time there the sandcaster ( well for me its more some shinigami) who will come to kill her so this world disappears and her with it....she will met her ln when was a child and the godess and she will even tell all to Erno at some point and he will even comes at some point come to takes her and he will send her grandma by the window ( sorry it was the best moment for me that and her who will speak her truth to her grandma )....so she will kill the bad guy and die in her real world imprint Erno and live in this world....
Not totally the end but yeah since for it to be completed she need to be dead in her Korean form it'll take lot of time if i remember well for her last fight begore her death it'll take 3 years in Korea and after that she'll be totally free....
Lucilliion will be with with her but the problem will be her memory will be little bashed so she wont totally recognized him until the last moment....
I'm only reading this for Erno at this point. Aerin is disappointing character, though it's mostly the author trying to show that she's moving in the shadows while pretending to be ignorant.
The setting makes me curious though, did she have influence on this world before she came here? Apart from Aerin, it's not a bad story, most of the characters are interesting, if clichéd.