|Relatives||Tsukune Aono (Son)|
Kyōko Aono (Niece)
Kasumi Aono (Wife)
|Voice Actor||Scott Freeman (English)|
Kōji makes about a few brief appearances. First, he appears as to explain to Tsukune how he found the entrance form to Yōkai Academy. Second, he's reading a newspaper as his wife is talking on the phone with Tsukune. Third, he's seen has his son waves goodbye to his friends returning to the monster world as a result coming home due to his wife's panic calls.
In the second series upon Alucard's defeat, Kōji along with is wife and niece watch on the televison of the battle's end.
In the first episode he is shown how he got the entrance form to Yōkai Academy. Later, he appears when the newspaper club, excluding Ginei Morioka, comes to visit and causes trouble.
Kōji is briefly seen at the end of Capu2 Episode 7 as a response to his wife's panic calls.
- "I'm the father."