Seiya Aido

Seiya Aido (藍堂, Aidō Seiya) is the child of Hanabusa Aido and Sayori Wakaba. He makes his first appearance in Vampire Knight Memories chapter 9.

In chapter 17, set a short time after his mother's passing, Seiya is revealed to have become a researcher helping his father with trying to find the vaccine for turning vampires human.

Personality
Seiya is known to be very loud when he has important news. He is also good friends with Ai Kuran, who often played with him as children. He respects her status as a Pureblood, but speaks to her as an equal much like how his father Hanabusa is on good terms with Yuki. (This is shown by Seiya calling her Ai-chan, instead of Ai-sama; chan typically is a term of familiarity or endearment, while sama is a term of respect for those with a position of authority.) Seiya tends to be a voice of reason for Ai when her temper gets the better of her, as she snaps out of her anger when he tries calming her.

He inherited his father's keen intellect and his mother's empathy; he could tell Ai hadn't found a loved one to drink blood from and offered his own blood, hoping that their friendship would be close enough to help sate her thirst. He also has a playful sense of humor, recalling embarrassing things from Ai's childhood. Seiya has his father's smugness, but balanced with Sayori's sense of right and wrong; he taunted a woman who viewed Ren's existence as a stain of the Kuran bloodline, but in a humble-worded way.

Appearance
Seiya largely takes after his father in looks. Though as an adult, his hair resembles his mother's more due to it being smooth curls instead of jagged strands like his father's hair. He typically dresses in a smart fashion and a lab coat while helping his father. However, he does have dress suits for soirees.