Dumb question... but what happened to the real "Elzay"?

When MC's soul got transferred to elzay's body, she got elzay's memory too, so MC's and elzay's memory merge as one, i think the young elzay is the real elzay since MC's soul hasn't transferred to her when elzay was young, but this only my opinion because i don't know any spoiler

Spoiler:






She lived her 1st life as Elizay but died young by protecting Aseph.
Bc the God cherist her, they send her soul to Korea for her to live her life.
But uk they wanted to give her a chance to go back to her original world if she wanted to, this is why they give her the book..
But bc the God powers were too weak, he could only transfer her at this age with loss of memory & unstable emotions (which explain why she's always crying lmao). Aseph is her soulmate too, but bc she died to protect him he became obsessed with her twin, & bc he sell his soul to the demon, the god didn't give him the mark he is supposed to have (someone tell me that he share his soul & mark with Elizay which why the prince find that her mark was strange)

Thank you @lucia_luce and @Nakisa for the explanation. UwU