I dont know if I got this correct but when the nephthys that loved seth got trapped by the mirror wasnt it because there was a part of her that felt some love for osiris? thats why Horus could go back from the mirror because he always saw Seth in the mirror? Idk I also felt sorry for her being sabotage like that by osiris
If the person reflected in mirror is not the same person u love in your heart then your soul gets split n half of u gets trapped in snd the factory reset version of u is outside who's magically made to be in love with the person u see in mirror. Osiris wanted seth to peer into the mirror so that he could trap him that way but neph looked into it accidentally and rest is history. Hathor wanted to do same to horus but seth was bullying hathor when horus looked into mirror n it was seth who's reflection appears coincidentally. But horus alrdy loved seth in his heart n reflected person is also seth therefore horus could leave the infinite void unlike neph who couldn't. But mirror hs another magic aka even if u leave mirror it befuddles your mind n intensifies uour innermost desire n makes u act upon it without uour will. It made horus rape seth agaisnt his wish. And it made nephyths conceive osiris child as her innermost wish was to have a child with seth so not only was she bewitched by mirror to love osiris she willingly had his child.
Hii if u dont mind i wish to plug in this reply of mine which goes into a bit of analysis and discussion on Seth's n nephs marriage and circumstances surrounding it. Itd be a good recap too since u haven't resd this in 2 years and u could take this as a clarifying pov..
Ah first comment is spoiler but I explain it in a reply.
https://www.mangago.zone/home/mangatopic/20010046/
Im feeling so conflicted right now over Seth and Horus being together (bc after finding out how in love Nephthys and Seth were in). I literally let this manwha marinate for two years and i come back to THISS bru i also liked Horus a lot back then idk why I feel conflicted of his character too