Hayato is a central character in the comedic setting of an elementary school classroom, serving as the primary point of sanity and reason among his peers and his unconventional teacher, Pascal-sensei. Physically, he is recognizable as a boy with dark brown hair and typically wears a blue shirt, presenting the image of a fairly ordinary student. His most defining trait is his personality, which stands in stark contrast to the chaos that constantly surrounds him. Hayato is fundamentally a serious and common-sensical individual, often taking on the role of the straight man or tsukkomi. He is the one who reacts with exasperation, confusion, or frustration to the bizarre and nonsensical behavior of his teacher and classmates, trying to ground the situation in logic. Despite this serious core, he is not immune to the show’s brand of humor and can become the butt of jokes himself, sometimes finding his clothes inexplicably removed in various gags, a recurring visual joke in the series.

Hayato’s primary role in the story is to be the anchor for the audience within the chaotic world of his classroom. As a student in Pascal-sensei’s class, he is often the one who falls victim to his teacher’s whimsical and illogical lessons. He is the target of Pascal-sensei’s antics and is frequently seen trying to correct or cope with his teacher’s incompetence, such as being unable to write his own name correctly. His motivation is typically simple: to get through the school day and to make sense of the nonsense, though he is often unsuccessful. In the anime adaptation, he demonstrates a degree of bravery and leadership, showing a willingness to help his friends and take charge when the situation calls for it, traits that give him a more heroic edge compared to his manga counterpart. His notable abilities are more about his mindset than superpowers. He possesses a high degree of common sense and a strong ability to pick things up or adapt to situations. However, like Pascal-sensei, Hayato has been shown to possess the power to transform into a form known as Super Hayato, a parody of super-powered transformations seen in other series. This transformation is a gag in itself, as it typically results in his clothes being torn off.

His key relationships are central to his character development. The most significant is his dynamic with Pascal-sensei, where he acts as the long-suffering student constantly bewildered by his teacher’s actions. He also interacts with his fellow classmates, including Chika, Steve, and Iwata, among others, often serving as a voice of reason in the group. While he does not undergo a profound emotional transformation, his character development is seen in his increased resilience and his growing ability to navigate the absurdity of his daily life. He has endearing personal quirks, such as sleeping with a teddy bear, making rounds at supermarket food tasting sections, and, according to Pascal-sensei, making a big fuss in the bathroom ten times a day. These small details flesh him out as an ordinary boy trying his best in an extraordinarily ridiculous world.