Is it bad for me to comment how all the guys in this game are super hot so the NTR isn't really NTR anymore. LOL I feel like NTR only works if the guy is ugly or monsterous looking but if the demon king is hot as hell, the dark elf is a tumblr sexy man and even the old guy is rather fine if you're into DILFs, its like "Im sorry Cross, how are you competing with these guys?"
Also, with how the prologue was and how everyone interacted, I can't help but just assume that Emma is just trans.
But I guess I'm probably missing the point as I'm diving in to get with the dark elf because he's too hot to resist LOL
That's kind of the point of NTR. It is about these seemingly more attractive options for partners that make the concept work, despite how shallow that is. If the original interest is notably impressive, possibly excluding the sex, the only rational belief at that point for a successful NTR is that the character being taken is just a shallow whore interested in sex and easily goes to the first person to "knock the rocks off," if I'm wording that expression correctly, at which point the NTR work is notably less engaging.
One of my favorite NTR works is a NTR of schoolboy with a schoolgirl, unfortunately the boy catches the interest of the Student Council President of the school, and makes her move to steal the cute looking boy from his cute girlfriend, starting with her popping his cherry in the Student Council Office, and nominating him to a seat in the Student Council so he is forced to interact with her more often than his girlfriend, and because she is the Student Council President and the daughter of an influential family of the school, he can do nothing to her without ruining his and the school's reputation, leading to his feelings for his girlfriend to be steadily eroded away by the notably more attractive and capable ojou-sama, as in the beginning fallowing chapters the President has been having sex with him between chapters, eventually leading to the final chapter where he is actively trying to pleasure her without thinking about how he is doing so with another girl than his girlfriend, or more specifically viewing the President with the same kind of love as someone in a normal relationship, even when the original girlfriend walks in on them having sex, unnoticed by the boyfriend, as the President looks at her and wordlessly mouths her victory of claiming him for herself.