Jiiya is first introduced into the series as Wataru's butler, who is looking after him, since Wataru's father is always traveling. After Wataru is suddenly whisked away to the dock that will bring him to his new school, he appears as a local fisherman, and soon after various other people on the island including a realtor, teacher, a shopkeeper, and even a doctor. What's the reason behind his "jack of all trades" role? He may be looking out for Wataru in a sense, but he has his own reasons as well, since he seems to know a great deal about his past.

Jiiya does not appear in the games or in Sister Princess RePure except for a picture of him that sits on Aria's nightstand.