Hanabusa Aido, nicknamed "Idol" by the Day Class girls, is known among the Night Class along with his cousin Akatsuki Kain to be "Kaname-sama's right hand". His fierce admiration for Kaname borders on zealousness and though extremely loyal to him, Aido has a tendency to overstep his boundaries, which results in Kaname punishing him if discovered. A noble-class vampire who can conjure and control ice, Aido often appears cheerful and friendly one moment, but vindictive and cruel the next. A perceptive individual, he figures out Zero is a vampire, but he keeps this information to himself without any hidden agenda in mind.
Aido is not overly fond of Yuki and dislikes the attention that Kaname gives her. He is temporarily troubled when he witnesses Kaname's killing of a fellow pureblood and runs away from the Moon Dormitory and imposes himself on Yuki and Zero. Agreeing with Yuki's assertion that he would remain loyal to Kaname even if betrayed by Kaname, he returns to the vampire's side. Aido has difficulty adjusting himself to referring to Yuki in a formal manner following the revelation of her true nature when he is appointed as one of her protectors.
During Rido's attack on Cross Academy, Aido protects the Day Class, as ordered by Yuki. Half a year after the incident, Aido becomes Yuki's tutor.