Unicornelia
Technically there's no NTR in this game, since the dev isn't anywhere near adding a relationship with any girl, nor seems interested to do it.
There's one of the girls that the MC spies having consensual lesbian sex with another potential (emphasis on potential) LI, and the two are clearly very close or even a secret couple.
The MC also spies the same girl being raped (extorted consent) twice and while he seems to sympathize with her, his mood is quite far from "hey, what are they doing to
my girl?"
On a train you meet a total stranger girl and the creepy ticket inspector blackmails her into sex, unless you pay her ticket.
After you can invite that girl into a couple of dates and have sex with her, but at the moment she is supposed to stay a side character and not a LI.
There could be other scenes that I missed, I didn't explore all the content, but still "not your girl, no NTR" is in full force in this game. Those are just strictly "voyeur" and not NTR scenes, if you ask me.
While this is still enough for some commenters to bitch until the NTR tag is added, I don't think netorare/sharing fans will get any kick from this content.
A different girl is apparently "claimed" by a friendly male character but she doesn't really feel the same, so the MC can have sex a couple of times with her (and if you play your cards right even a FMM threesome with the aforementioned guy), your call if this is cuckolding your friend.
cxx
Oh, no... not another Ruby!