What can I know about it, I'm not South Korean nor I stan their culture, hence no knowledge about the laws.
Just pointing out again what others already said within eTIRUe threads.
Also I was talking about full nudity, if it was not clear enough.
You on the contrary, talking about NTR is no sense: are you talking about Full Nudity NTR scenes ?
As far as I know, the issue could be in whatever thing: maybe being a 2D comic could be permitted, maybe the issue could be about 3D / 2.5D models.
Maybe he just would need to get authorized by the government, but could have downplays to obtain such authorization.
Who could know...
Maybe the NTR scenes you are talking about were not with full nudity in display: surely you not pointing out what are you talking about in the specific, doesn't help nor provide enough context to give you a reply regardless of my lack of knowledge or not.