Every time someone writes down their idea of what NTR is i see something different. I am convinced that i have never seen the same definition being used twice on what NTR is, at this point i'd say NTR is just as subjective as music taste.
For example for Oriandu, based off of my understanding on what he wrote, something can only be considered NTR when you're in a relationship with someone and that someone is having an affair, therefore he's obviously not gonna see the first two HC games as NTR because the MC was not in a relationship with anybody in either those games.
As for me, i think Family members being seduced IS NTR, i especially like sister NTR so obviously for me the first 2 games are NTR as well. (real sister NTR >>> step-sister NTR).
What i mean by that is that neither of us are necessarily in the wrong, it's just that you're not gonna get 1 definitive answer by asking "what's NTR" on this site because everybody's got their own idea of what NTR is in their heads.
This is a pretty surface level description but that's basically how I would describe it as well so...here you go.
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