Yuki & Kaname

Yuki Cross and Kaname Kuran have a long history and have a complex, if somewhat at times, mysterious relationship.

Background
It is mentioned both in the anime and manga that Kaname and Yuki Kuran were engaged to be married since they were children. This is a common practice among purebloods to preserve their bloodlines.

History
Kaname once declared that Yuki was born to be his wife. As a child, Yuki adored her older brother and the two shared a close relationship. Due to fears over her safety, Yuuki's birth was kept secret from the rest of vampire society, and for the first five years of her life, she was kept hidden from the outside world, locked in the basement of the Kuran manor with only her parents and older brother as companions.

Yuki's parents managed to keep their daughter safe until the night Rido Kuran attacked the Kuran household, killing Haruka in the process, and spurring Juri into sacrificing her own life in a final attempt to protect Yuki by transforming her into a human. After severly injuring Rido (but unable to land the killing blow), Kaname took the unconscious Yuki to the home of Kaien Cross, a vampire hunter and longtime friend of the Kurans. Upon awakening, Yuki no longer remembered the first five years of her life, instead beleving that she had been saved from an angry vampire in a snowy field by Kaname, giving Kaname the lasting impression of a savior in Yuki's thoughts.

Yuki then spends the next 10 years of her life living as Kaien's adopted daughter while Kaname is taken in by the Ichijo family under the watchful eyes of the vampire council.

During this 10 year separation, Kaname is frequently tricked by Kaien into visiting Yuki, opportunities which allow the two to grow close once again, and which gives Kaname a temporary respite from the vampire council. With Yuki, Kaname is able to laugh and relax and behave more like a normal teenager as he fondly watches over her. Kaname also makes it a point to visit Yuki each year on the anniversary of her being saved from the angry vampire, a day Yuki calls her birthday. The human Yuki grows trusting and fond of Kaname and holds a strong belief in his kindness based upon his gentle caring of her. She soon falls in love with Kaname and begins looking forward to each of his visits.

Yuki and Kaname's relationship changes after the creation of Cross Academy. Knowing Kaname is living nearby in the school's dormitories, Yuki decides to pay him a visit. Unable to locate him, she falls asleep on the dormitory stairs while waiting for him. Kaname finds her soon afterward nearly gives into the temptation of drinking her blood, stopped only at the last minute by Ruka. Kaname then takes Yuki to his bedroom and proceeds to drink Ruka's blood in an attempt to quell his hunger. Yuki awakens while Kaname is still drinking Ruka's blood, the scene causing her to run off in shock and fear. Finally having come to understand that vampires and humans truly are different from one another, Yuki's relationship with Kaname becomes more distant than it once had been, to the sadness of both.

Prior to Yuki's Awakening
At the beginning of the series, Yuki is 15 years-old and a first-year student in the Day Class at Cross Academy, where she also acts as a school Prefect/Guardian. As the Night Class president, Kaname is one of the most popular and influential students at Cross Academy, and seemingly unreachable for a normal girl like Yuki. However, the Night Class share a secret which only the school Prefects, Yuki and Zero Kiryu know: they are all vampires, and Yuki and Kaname also share a secret past of their own: Kaname once saved Yuki from a vampire when she was 5 years-old. Thanks to this, Yuki regards Kaname as her savior and the two enjoy a special bond. Kaname calls Yuki his "dear girl" and Yuki quietly returns his affections, though often feels awkward and inferior around Kaname due to his status as a respected Pureblood vampire.

Although Yuki states that she is in love with Kaname, she finds his attachment and his gentleness toward her inexplicable as Kaname spends much of the first arc working to protect Yuki, which includes killing Shizuka Hio and fostering Zero's powers.

Yuki's awakening
Kaname is forced to bite Yuki to save her from the danger of Rido Kuran and to relieve her pain as she "breaks" from the inside. Kaname reawakens her vampire side that was laid dormant by Juri. Yuki is initially disturbed upon her awakening at the thought of being in love with her brother, but then Kaname reminds her that they are engaged and she remembers their mother and father were also siblings and that she and Kaname promised someday they will be just like them.

When Kaname wants to leave the school with Yuki, she stubbornly refuses on the basis that she needs to fight Rido and she wouldn't be forgive herself if she ran away. Kaname is unhappy, having previously lost her when her memories of him were erased and he suffered without her for 10 years. She kisses him and promises to return to his arms. After the fight with Rido is over and she parts with Zero, she returns with Kaname to their family home. There Kaname finally confesses all that he has done to protect her, including using Zero's bond with Yuki. Yuki is initally upset, but realises that she is hurting Kaname by pushing him away. She accepts his sins and wishes to share the responsibility for his actions, share his pain.

Yuki stays inside the Kuran mansion for a year, to keep her protected and to learn how to use her fangs again. Yuki has returned to calling Kaname "Onii-sama" and occasionally "Kaname-senpai" despite his repeat requests to simply call him "Kaname". Kaname is frequently away and she looks forward to his returns. She suffers from bloodlust and hunger, desperate for Kaname's blood. She reveals that Kaname alone cannot satisfy her hunger and expects Kaname to reject her request to stay by his side.

Kaname accepts it and tries to impress upon Yuki his need for her, going so far as to state that he would rather kill her or be killed by her rather than being apart, causing her to wonder "why it was [her]". He goes as far as telling her that she would have to kill him if she left him. The next day he returns the Artemis to Yuki to show the severity of his words. She takes this as his approval to do as she pleases.

Yuki leaves the house and gets into trouble after being attacked by another pureblood, Touma, whom Kaname severly punishes for hurting Yuki. Kaname then reveals that he fears losing her deeply as has happened before to him.

Kaname the ancestor
After finally telling Yuki that he is not her real brother, Yuki drinks Kaname's blood to see his memories, she sees his awakening by Rido, which includes the murder of her true brother and Kaname's distant past as the ancestor who saw the rise of vampires. He fought to ensure humanity's survival, following another vampire who created the hunters and saw her death which created the Vampire Hunters and greatly affected Kaname.

Yuki asks Kaname if the hooded woman can be replaced, Kaname assures her that no one is ever a replacement for another, inadvertently refering to Yuki herself. Kaname eventually lies down to sleep forever after all his companions die and he is the last left of the ancestors.

Yuki awakens from the memories and frantically searches for Kaname after finding herself alone and confused. She finds Kaname and expresses her upset that she did see her brother's face upon waking. Kaname understands that its hard for Yuki not to think of him as her brother since he took her brother's life. Yuki understands and says she will call him "Kaname" from now on.

Aido-dono asks Yuki if she would be able to stop Kaname if she thought he was doing something she disagreed with and Yuki states that she will not be about to do anything while she is still not Kaname's equal. Her vampire inside expresses the desire to devour Kaname completely and tells her she will go crazy if she does not eat what she wants. Yuki acknowledges she has been too busy with her problems to consider other things.

When Yuki stumbles over calling Kaname by just his name, Kaname offers to let her rename him if she is jealous. Kaname asks Yuki what she thinks of him, she tells him that she knew him as her brother, her senpai and now he is the ancestor. She says that Kaname is a beast like her, but he is a bit weak, lies, is dodgy and has too many secrets. She is also a bit uncertain of his feelings for her, but amends that he loves her but there are other things mixed up in his feelings for her. Ultimately her best answer to his question is to ask if they can start over and she can watch him properly, to which he hugs her tight and agrees.

After saying goodbye to Yuki, he leaves saying that he has very important duties to attend to, leaving Yuki alone in the mansion. Yuki, still confused by his last remark to her, runs out of the mansion to clarify what he just said to her. After meeting up with Kaien, she soon finds Kaname with Aidou's father. Kaname slays the head of Aidou's father.

Soon afterwards, Kuran was marked as a "dangerous" vampire, and Yuki gets taken away by the hunter's society for further questions. Saying that she didn't know what Kaname's intentions were and also saying that she only wanted peace between vampires and humans, the meeting ended.