To outsiders Karin appears to be a normal, cheerful high school student. However, Karin and her family are all vampires. To make matters worse, Karin is not even an ordinary vampire - she is a blood maker and must inject the excess blood into her victims! If she doesn't find a victim to bite in time, her extra blood is expelled in the form of a massive nosebleed. Karin's already difficult life is made worse when Kenta Usui transfers into her class and she finds her blood increasing at an alarming rate. When sharing classes and an after school job together make avoiding Kenta impossible, Karin must find a way to keep her rapidly increasing blood under control or risk exposing her family's secret.
Both Karin and Orange Marmolade are vampire themed romance series. Both of them feature a vampire girl in a high school setting. In both cases the girl tires to blend in and not attract unwanted attention from her human classmates. Those series also feature a vampire family who supports the female lead. I think, I don't need to mention that said girl's love interest is a human boy. The style of those series might be a tad different, but if you liked one of those, the other one should still prove interesting.
Both are romance stories about a vampire girl who tries to go through life without attracting attention to herself. The girl then falls in love with a human boy and the story unfolds from there.
I'd say Orange Marmalade is less comical, and rather more serious. It's also the better of the two by far, but if you like vampires and romance then each of these should hold your attention!
Plain Kaya Satozuki has just accepted a position as a secretary for Kyouhei Touma, a young company director whose lecherous ways are renowned. While she initially believes Kyouhei is just a typical, lustful man, Kaya soon discovers there's far more to Kyouhei than meets the eye: he's a vampire, and he requires the blood of women to survive! However, he doesn't kill them - he seduces them and bites them gently in the climax of pleasure without leaving any marks behind. Now that she knows his secret Kyouhei insists she stay on board, scheduling his ‘meals' in tandem with her secretarial work. But soon, Kaya finds herself falling for Kyouhei and helping to feed him when needed. Thus begins Kaya and Kyouhei's troubled yet thrilling relationship that is filled with trials and tribulations aplenty.
If you found that bastard Ren somehow interesting, you might want to give Midnight Secretary a try. The male lead there is strangely similar to Ren. On the other hand if you didn't like Ren, stay as far away from Midnight Secretary as possible.
The one real similarity between Toradora! and Karin are the male leads. Both of them were raised by a single mother and both of them grew up with the potential to become a housewife...
Considering how common it is in shounen media, you might find if refreshing that neither of those two is a pervert. Both of them care for their woman because they love them rather than because of physical attraction (I'm not saying that there isn't any). What's more, in both cases said love is something that evolves from friendship and takes some time to "hatch".
So if you liked the male lead and romance in one of those two series, the other one should be worth checking out as well.
Yuki Cross' earliest memory is of snow and blood - she was attacked by a vampire only to be rescued by another. Ten years later and Yuki has been adopted by the headmaster of the prestigious Cross Academy. This school is unique in that it consists of 2 classes - a Day Class and a Night Class. The Night Class is made up of vampires led by Yuki's rescuer all those years ago, Kaname Kuran. Together with Zero Kiryu, a childhood friend who despises everything to do with vampires since his family was murdered, Yuki must serve as a Guardian of the school to keep the two classes separated. Secrets lie beneath a peaceful exterior and not everything is as it seems, as Yuki learns the truth about Kaname, Zero and her own forgotten past.
Chibi Vampire and Vampire Knight are both blossoming romances between human and vampire. In Chibi Vampire, the Karan is a reverse vampire who instead of drinking blood needs to expel it. Though Vampire Knight is a bit more mature than Chibi Vampire I have no doubt fans of vampire romance will enjoy both.