I think it's interesting to compare the way Aki was groomed vs the way Denji was groomed
And I have some thoughts on it
Himeno and Makima are two very different kinds of groomers, in Makima's case she knew exactly what she was doing and she understood that Denji is a child who is very easy to manipulate because of how vulnerable he is
In Himeno's case what happened is she "adultified" Aki in her head. Himeno is emotionally immature and I'm not sure whether or not she really understood what she was doing to Aki. Aki ended up believing the same thing she did, that they were equals and that he was an adult. He felt like he had to take care of Himeno to some degree. If you asked him, I'm sure Aki would be completely unaware that he was being treated inappropriately. Himeno had seen so many people die around her I don't think she had the opportunity to actually view herself as an adult and that combined with her desire to feel loved and her correct belief that she would die young made her latch onto the affection she got from Aki
Makima's abuse comes from her not seeing Denji as an equal and Himeno's comes from her seeing Aki as an equal
I think I'm gonna come back to this later and expand on it and add screenshots
