despite the fact this manga has amazing art and decent plot, it's just weird. nazuna is an adult vampire, and you can tell from hints like the fact that she legally does drink beer and she owned one of those blocky cellphones before the flatter ones came out. ko is a child, he states that he is 14, and he goes to middle school. and they're supposed to fall in love; and even go as far as to have "sex".
now, to be fair, "sex" in this manga, or at least what they do as a vampire and a human, is just nazuna sucking ko's blood. but its emphasized how that's purely an intimate and physical experience.
the target audience for this anime is also clearly targeted towards the male gaze. the women in this manga are sexualized and objectified a lot, with flattering shots of akira's thighs, and a bunch of sexual imagery of nazuna. It just enhances a never-ending problem with the animanga industry. I've seen so many people hyping this up, but it's just uncomfortable to read.