Mr. Aizawa is Sakuya's father. A man with a strange sense of humor, he is apparently proud of his 'naked conversation skills', much to his children's horror. Despite this, he gets along very well with his younger children.
He first appeared in episode 23 of the second season of the anime. He offered Nagi a salmon but she declined the offer. In the next episode, he was seen triggering his own trap set for the missing Nagi.