Episode 21: Spiraling Recollections

Spiraling Recollections (追憶の 螺旋スパイラル, Tsuioku no Supairaru) is the 21st episode of Vampire Knight.

Premise
From Amazon/Viz Media:

"Yuki wakes up a vampire, and her memory of her childhood returns. She now remembers her father, her mother, and her brother. Despite her mixed emotions, Yuki cannot suppress her vampire instincts."

Summary
Kaname reveals to Zero that Yuki is the Pureblood Princess of the Kuran family and asks him what he will do because he hunts vampires. Kaname carries Yuki off to the Headmaster's private quarters, leaving Zero unable to shoot the Bloody Rose at either of the vampires as he was in shock. Yuki recalls her past, that Kaname was her older brother, and her mother and father sacrificed themselves so that Rido would not be able to harm Yuki. Yuki's father Haruka Kuran died fighting Rido and her mother Juri Kuran used her remaining life to seal away Yuki's memories as a vampire, also turning her daughter into a human. The smell of blood alerts the other vampires of the Night Class that Yuki is, in fact, a Pureblooded vampire.

Kaname meets Akatsuki and Hanabusa, and explains that Yuki is younger sister and his fiancée, as long as she chooses to remain so. Upon awakening, Yuki drinks Kaname's blood to revitalize herself and sees the scene that had tormented Zero after he drank Kaname's blood then is saddened that her parents sacrificed themselves to save her and begins to cry and shatters the glass in the room out of anger. Yuki then realizes that she's in love with her older brother and Kaname doesn't have a problem with it before licking some blood off of Yuki's lips.

Yuki realizes that her mother and father were also siblings and Kaname reveals that they are engaged, and that Pureblood vampires often marry within the family to maintain the Pureblood blood line, though this fact appears to disgust Yuki as it is something only beasts would do.

Kaname orders that the day students are to be kept in their dorms, guarded by the vampires who can appear in the sunlight, among them an apologetic Ruka, still hoping to prove her value to Kaname. Meanwhile, Rima battles Rido, in the body of Senri. Just as she is about to lose to Rido, she calls out to Senri within him, awakening Senri and momentarily suppressing Rido. Yuki decides she wants to speak with Zero and escapes her room, ordering the guards that Kaname has placed for her protection - Hanabusa and Akatsuki, to let her go to the Day Class' Dorm (where Zero is). Despite Yuki's conscience telling her that she is now a monster that Zero loathes, and her actions to speak with him would be futile, she proceeds. As she approaches Zero's room, she hears Zero point the Bloody Rose at her through the closed door to his room.