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I mean if you see a person with a semi pixelated face, you'll call them ugli too probably. I'm not sure where you're up to in the novel
Slight Spoiler ahead
At one point, his friends tries to remember what he looks like to try and explain why they call him ugly but they find that they couldn't remember his face at all. Like his face was never registered in their minds and memories and were always covered by a layer of fog. This maybe because of his status as a "reader".
I still havent finished the novel yet (taking a break cuz yjh x kdj tension too high) so idk if his fuzzy existence will be further explained.
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I already finished the novel and I might have a idea why they can't see Kim Dokja real face
SPOILER ALERT
Kim Dokja actually a being who make Ways of Survive in The Ruined World become reality. The 4wall protect his status and face to prevent harm to him because I think he basically the real god of that world.
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Hmmm I think his face will change right?
I just put a space on it because it will be a spoilers for others... When he become a constellation and he died, his own incarnation body died right? Then a time he need to find a body of an incarnation to use for him to live again? So maybe his face will change but a bit similarity with his original face..
I don't really know why they call Dokja ugly in the novel but he seems to have a great face than Lee Hyunsung (for me).... Or the Novel's protagonist is really more handsome than Dokja...