Aidou Hanabusa
Aidou (Idol) Hanabusa is one of the illustrious night class vampire students of Cross Academy. All of the female day class human students have a huge crush on him. He is the flirtatious one among the vampires and enjoys the limelight.

This blue-eyed cassanova possesses the ability to control ice. While he is normally good-natured and cheerful, he has a very vindictive and aggressive side to him. He can also be very rebellious, which oftentimes results in him being punished by Kaname. Nevertheless, he still remains fully loyal to the pureblood.

Kurosu Yuuki
Kurosu Yuuki is the prefect day class student / headmaster's daughter. As a prefect, she puts a lot of dedication to her job of maintaining the peace between the night class students and the day class students, and preserving the secrecy of the vampires' identities. She remembers nothing about her childhood before the day she was saved by Kuran Kaname from a bloodthirsty vampire.

Aidou Hanabusa + Kurosu Yuuki
Aidou and Kurosu are shown immediately in Episode 1 of Vampire Knight. We see their first encounter one night when two day class students decide to sneak in at night and spy on the handsome vampires. Aidou goes to them, hungry for a diet aside from his usual blood tablets. This is when Yuuki shows up to protect the two girls. Aidou ends up preying on Yuuki instead, remarking that Yuuki's blood is sweet, until Zero and Kaname finally show up to save her.

Over the episodes, we see that Aidou hardly shows any respect to Yuuki, mainly because he does not understand why Kaname loves her so much. In one of the episodes, he even goes so far as to threaten her with his ice powers. Nevertheless, because of his loyalty to Kaname, he puts up with her. In several instances, he teases her, and acts all affectionate with her when jealous day class students are looking.

The turning point of their relationship happens when

We can only imagine how their relationship will progress from there, and wait for the new Vampire Knight manga chapters to come out. I would surmise that their friendship will deepen. Aidou developing stronger feelings for Yuuki may also be a possibility.