This anime has no plot. Literally. You would think that an anime whose premise is a girl surrounded by six vampires would be interesting and mysterious, well, no. There are literally not many spoilers to tell as there is not much to tell! If you are going to watch this, keep in mind that you will only see a girl being abused, and nothing else. There is no reflection, there are no moments where you look for empathizes with the protagonist because of her torment, but you arrive at the moment where you simply know that this anime aims to get girls horny by bringing "erotic" scenes of physical and psychological abuse of six sexy vampires to a girl with no personality. And here comes another point, the protagonist has no personality. And I'm not saying it to be rude on purpose, but the only words of the protagonists are No! and Stop! but deep down it gives the impression that she ends up enjoying it, which makes this even more horrible.
This anime is targeted to females, which makes it even sicker, as if we find enjoyment or something "cute and romantic" in such things. Therefore, it is a just misogynistic anime. There are scenes so cruel, without being bloody. that they are equivalent to group sexual abuse, where two vampires approach her to bite her, but it is not difficult to reinterpret the scene.
Another point is that this anime does not appeal to anyone. Do you like vampire stories? Well you won't see that here, just guys abusing a girl with the excuses of being "vampires". Do you like teen romance between girl x something? There is no here, they do not love her nor she does, there is only abuse. Do you like perverse shows? This is not even good at it, since it's super edgy.
There are times when you can't even be outraged because you no longer take what happens seriously, but the series tries to seem respectable even adding past to the characters so that in the end they do not develop, they do not arise, nor is there an characters arc, they are there only to justify the actions of the characters.
It is an insulting show in many ways, and not only to women, but also to the genre of vampires.
The worst thing is that the anime is not presented as an anime of abuse and eroticism, but a vampire story, which it is not. It is a story of six wicked boys abusing a hyper submissive girl wrapped in a vampire atmosphere with no plot background.
Only the soundtrack is slightly enjoyable in this anime, which could be one of the worst ever.

But let's face it, things like these wouldn't exist if there wasn't a demand. It is really sad that people consume this and like it, or try to justify the characters. Pathetic.
If I had to rate it I would give it 3/10. 3 because its soundtrack is decent, the opening serves its purpose, and the animation is sometimes a good thing.