Vampire Knight

loses her virginity. and I thought Kaname killed every other pureblood except himself and Yuuki. I must be mistaken.

Kaname saw how corrupt purebloods were so he decided to kill them all. In order to do this, he had to detach himself from everyone (Yuki in particular), so they wouldn't be caught up and blamed for the ensuing bloodshed. To help further this goal, he pretended to kill Aido's dad (which was possibly prearranged between them), which made everyone doubt him. Yuki tried to stop his crusade because A) she still had feelings for him and didn't want him to be like that, and so he could face justice for Aido's dad. This included protecting Sara, who was just very good at playing the role of the victim. (It's been said time and time again: purebloods are very charismatic.)

Then, when Kaname finally killed Sara, things went crazy. I don't know if he planned it or not, but the "parent", A.K.A. the heart of his original lover, recalled almost all weapons and pretty much went dormant or something. So Kaname decided to become the new "parent" using his own heart, which will result in his death. At the same time, Yuki, still having feelings for him and wanting him to face some measure of justice, decided she should make him human. By making him human, it would render him unable to do anything else, thus ending his tirade without killing him, which she still couldn't bring herself to do because she still loved him a certain degree. (In her defense, killing the person you love is a LOT harder than you'd think, no matter how crazy or evil they go.)

However, this would kill her, which would have a heavy impact on Zero. As such, she erased his memories of her, which apparently helped cure his thirst. (Trying to remember how that works, but probably has something to do with the seal the chairman set up at the start of the manga.) Then the chairman revealed all of Kaname's plans in front of Yuki, and this ultimately allowed him to finally ally with the hunters and reunite peacefully with Yuki. He still plans to become the new "parent", though. Yuki, in turn, realizes he's done everything to protect her since her "birth" as a human, and is now trying to talk him out of his sacrifice so they can FINALLY be together.

However, the other purebloods aren't too enthusiastic about Kaname's plan to die and create new weapons to kill vampires. As such, they're probably planning to kill him during this night, since someone mentioned "throwing your heart into a furnace tomorrow". In short, this is the final arc, and then all this convoluted-ness will be over.

After all the bs, she concludes to make Kaname human? Honestly, the only thing that's remained the same since the beginning is that Yuki is a stupid, selfish girl.