Akasaka Mamoru

He is a detective in the Tokyo Metropolitan Police Department's Public Safety Division who lost his wife, Yukie, five years ago. Now lives alone with his only daughter Miyuki.

After the Great Hinamizawa Disaster, he cooperates with Ooishi, who is working hard to solve the mystery, and visits Kakiuchi City to find out who is from Hinamizawa Village. He tells Natsumi and the others that he is from the "Okinomiya Bookstore".

Protagonist of Himatsubushi and one of the protagonists of Kageboushi.