Got off on a bit of a tangent there, but the fact remains that I didn't think much of Karin at first glance. For one thing, the name of the series eventually became 'Chibi Vampire' or Little Vampire in English, which is a bit ominous. The characters all seemed cutesy and sort of flat at first and it also had a gimmick which I figured destined it for low-brow slapstick. More on the gimmick later, as I should mention my initial doubt about the series was probably also heavily influenced by Rosario + Vampire. I really wanted to like that show and felt pretty ambivalent about it. It could have been so much better if there were simply more plot and less fanservice and i had the sinking feeling that Karin might follow in the same tracks. Luckily, I was wrong.
The main plot of Karin is the eponymous heroine is a vampire living in modern day Japan with her family. While the rest of her family are normal vampires, Karin herself is a bit different. Instead of biting humans to suck their blood, she's actually a blood producer. When she bites people it's actually to inject her excess blood into them. If she fails to do so, SWOOSH, she ends up with a nosebleed like mount saint helens going off and it looks like someone butchered a cow. See what I mean about the gimmick? This also means that my entry title actually has some witty relevance and simply wasn't me reveling in some misogyny. Mmmm, sweet, sweet misogyny.
Back to the plot, it turns out that all vampires have a blood affinity. This means that they prefer the blood from certain individuals. Her mother prefers liars, her father prideful men, her brother stressed people, her sister the envious, and she, herself, has an affinity for the unhappy. Instead of wanting to suck the blood of those individuals, whenever she's around an unhappy person her blood production goes into overdrive and unless she gets out of the area....slaughterhouse. You sort of have to wonder, given how moody teenagers are in general, how she manages to get through even a single day of school without spewing blood like a supersoaker. Instead, she only bumps into Mr Unhappy when he transfers into her school and thus begins the romantic comedy portion of the anime as she tries to make him happy by making him bentos in the hopes that it'll stop her blood explosions.
The other side of the plot involves something a little more serious as the family tries to find a way to turn Karin into a real vampire as opposed to an un-vampire. Once vampires mature, they can no longer go out during the day because they get burned by sunlight. Her little sister hasn't fully matured at the start of the series and so still manages to keep Karin company during the day and help her out, but that won't last forever. The family feels like they'll be abandoning her if she's forced to live as a normal person while they, obviously, cannot. Toss in a vindictive vampire hunter who holds a grudge against the entire family along with some interesting backstory and that's it in a nutshell. From what I've read the manga plot is even more intricate and hardcore, featuring much darker themes as Karin may be the cure for growing Vampire infertility and a cabal wants to capture her, rape/impregnate her so her 'line' continues, and then bleed her dry as the source of the vampire viagra. While the anime ended pretty happily with status quo + new love, the manga was more bittersweet. Her family knows that she can't stay with them and will never be happy pulled between two worlds so they ask Kenta (the boyfriend) to give her all the happiness he can and their share too and erase all memory of her family. She's then free to live her new life without any of the dark entanglements of the past, though her family still loves her and watches over her from the shadows. I enjoyed the more fluffy anime-only plot enough that I'll probably also get around to reading the manga at some point too.
On a sidenote, the mangaka for this work apparently has a really weird fetish for nosebleeds. I have no clue how one develops something like that but she's apparently all gungho about them. In both the anime and the manga, the blood fountains are often depicted as streams of red flowers, no doubt to avoid grossing out the audience. As someone who has had to spend a lot of time dealing with blood and its explosive/leaky aftermath, I just have to say that she must spend a fortune on clothes/drycleaning.