Airu is a young man of tall build with short black hair swept to his left and brown eyes. He almost always has a serious and intimidating expression. He wears a pair of black gloves on his hands, a red tie with the normal uniform of the school, and a band on his left side and having a little longer the sack than the one of the others students, to distinguish him as a Prefect.
When not wearing his school uniform on, he tends to wear a kimono.
Unlike his delinquent younger brother, Airu is very intelligent and diligent in most regards. As a result he is serious, strict, and often comes across as cold when leading the Black Doggy House. Despite this, he shows a softer side to children.
Since his father's death, he has most responsibilities and upholding the family's status and takes great pride in it. He will not take it lightly if the slightest tarnish appear, as seen when he keeps his brother in line though he does seem to love him and shows care towards him.
- He is one of the few Black Dogs not to show hostility to the White Cats House.
- He likes dogs, but dogs are very afraid of him.
- When he was a Prefect, he decorate his room with traditions from Touwa.
- There was consideration for him to be named "Dobeo" after a Doberman, but it was immediately rejected because the author thought the idea was lame.