The Kinjirō Ninomiya Statue is modeled after the real-life statues Sontoku Ninomiya, being a young man with hair tied into a bun and a slightly pointed nose. He is dressed in a short kimono and hakama, with a harness to carry around firewood and a book in his hands.
The Kinjirō Ninomiya statue has a bit of a mischievous side as he runs at night around the school to prank the humans, otherwise not much is known about his personality.
Nino is a friend of Sunakake-Babaa, Konaki-Jijii, Ittan-Momen, Nurikabe and the others. When he did not respond to their messages from a few months ago, they suspect something had happened to him and went to check on him. Later he is found along with the other seven mysteries that were captured by Yōsuke-kun, and were hung up in the gymnasium when he believed they were after Hanako-san. After Yōsuke-kun was defeated, he is rescued and returns back to his post.
The Kinjirō Ninomiya statue is based on the real-life statues of Sontoku Ninomiya (born Kinjirō Ninomiya) placed around school grounds, which is said to come to life at night, just like the anatomical model.