I think 'a knowing sister manhwa hentai' could imply a manga that involves a sister character in a somewhat risque or adult-themed situation. But without more information, it's hard to say for sure.
It usually features explicit and adult-oriented content related to a sister character with some form of awareness or knowledge. But such content is often not appropriate and may be against moral and legal norms.
Overall, the adaptations of 'A Knowing Sister' manga maintain the essence. There might be some minor changes to suit the medium, but the main plot and characters remain intact. These changes are often made to enhance the audience's experience and keep the story engaging.
The anime of 'A Knowing Sister' is known for its faithful representation of the raw manga. It keeps the core elements intact and the storyline consistent. Although there are occasional artistic adjustments, they are in line with presenting the manga effectively on the screen.