Makio's appearance in junior high: He has short blue hair that stops near top portion of his forehead, it is parted on the left side.
Tanihara is a somewhat foul mouthed and crude guy. He has a past of bullying people, especially Miyamura. However, in situations where he is uncomfortable, he becomes very quiet, tending to internalize his thoughts and letting others act first. He has a minor fear of girls, in part due to the many girlfriends that his womanizing brother has brought home with him, as well as his own experiences with the many female characters in the series. Aside from this, he's relatively diligent, especially compared to his older brother.
In junior high, Tanihara ignored and bullied Miyamura, especially in group activities and projects. Despite Shindou becoming friends with Miyamura and sticking up for him, Tanihara and his friends continued to bully him. In high school, a chance encounter between the two began with Tanihara continuing to bully him. However, Hori, who was with Miyamura at the time, beat up Tanihara. Later, after witnessing Miyamura being violent with Hori, he came to fear Miyamura, thinking he was now even more dangerous than Hori.
As Miyamura began to pursue a friendship with Tanihara, he was originally resistant, partially worried that Miyamura was trying to pursue him romantically. However, after spending much time together, he now considers them friends, and him, Miyamura and Shindou can often be seen together.
Tanihara and Shindou are friends from junior high school. They had a slight falling out after Shindou began spending more time with Miyamura, but continued their friendship through high school. After Miyamura is also added to their group, Tanihara plays the role of the straight man, trying to keep Shindou (and Miyamura) in check. He sometimes gets tutoring from Shindou, and is described to be a quick learner once it's explained to him.
Okuyama has taken a liking to Tanihara, despite his claims of not being good with children, and treats him like an older brother or guardian. While Tanihara does nothing to foster this image, he also does not actively discourage it. Although Tanihara usually stays silent when with Okuyama, she more than makes up for it, often telling him the details of her day, just like a child would tell a parent. In the rare occasions when he does speak, it's usually to give some brotherly advice or consolation to her. Tanihara also seems unaware of Okuyama's real name, usually referring to her as "Margarita", which is actually the name of the stuffed animal that she gave to him.
Makio frequently badmouths his older brother, usually calling him a useless NEET or other similar terms. Makio views Youji as unreliable, and Youji, with all his requests to borrow money and his playing around with girls, does nothing to counteract this image.
Tanihara is deathly afraid of Hori. After getting beat up by her during their first meeting, he views her as an oni, and later, after seeing her jealous side, a hannya. This also makes him (initially) even more afraid of both Miyamura and Sengoku, as he witnesses both of them hitting Hori without her retaliating, making him think that they're even more powerful than her.