Its just people placing themselves in the cuck chair. NTR refers to stealing someone's partner. Chika is a society outcast, put simply. When you first meet her, she is basically the full package, tats, smoker, sleeps with yakuza etc etc. If you interact with her you learn her backstory and it is made fairly obvious (unless the dev jukes us) that you will be steering her off that path. We haven't done so yet because the game does not have that many versions released thus far as of writing. We have not dated her, did not know her for long etc, so where the NTR comes in I have no idea.