Arata is a university student who was once a dedicated member of a track and field club, which gave him excellent physical conditioning and agility. He is also deeply passionate about the culture and techniques of ninjas, often incorporating this fascination into his daily life in eccentric ways. His defining characteristic, however, is his immense love for cats, a fondness so profound that it nearly led to his transformation into one of them. He was rescued at the very moment he was on the verge of turning into a cat. Arata has brown eyes and gray hair that reaches his ears, and he is typically seen wearing gloves and armor.

Arata's personality is energetic, playful, and loyal. He brings a sense of enthusiasm to any situation, though his self-proclaimed ninja obsession makes him appear a bit eccentric to others. Despite his athletic past and his drive to improve his skills, he does not take himself too seriously and possesses a particular kind of humor. He is described as open-hearted and sensitive, with a deep capacity for affection, especially towards felines. This balance of strength and gentleness, combined with his unique mannerisms, makes him a distinctive presence in his group of survivors.

After being saved from cat-ification, Arata's primary motivation becomes his profound gratitude and admiration for his rescuer, Kunagi. He begins to look up to Kunagi as an older brother figure, or "Aniki," and this relationship gives him a new sense of purpose in a world overrun by the Nyandemic. His love for cats remains a core part of his identity, and his actions are often driven by a desire to protect both his friends and the felines he adores. He joins Kunagi and other allies, such as Kaoru, on their journey through the desolate dystopian landscape, searching for other survivors.

In the story, Arata serves as a key ally to the main protagonist, Kunagi. He is part of the core group that navigates the dangers of a world where cuddling with a cat leads to transformation. His role is that of a supportive and energetic companion, using his physical abilities to help the group survive. His relationship with Kunagi is the most significant; he follows him closely and treats him with deep respect and brotherly affection. He is also shown interacting amicably with other survivors, including the Last Samurai, a character he spars with and discovers is a young woman under her armor. He eventually takes refuge with the group in a settlement led by a woman known as Grandma.

Arata's development is centered on his transformation from an ordinary university student with quirky interests into a survivor with a clear purpose. The near-loss of his humanity to his love for cats becomes a turning point, solidifying his bond with Kunagi and his commitment to the group. His character also provides moments of levity and comic relief, as his ninja antics and cat-obsessed behavior contrast with the grim setting. At one point, he appears in non-canon comedic segments about cat care, highlighting his playful nature. He continues to refine his self-taught ninja techniques throughout his journey.

Notable abilities that Arata possesses include the physical prowess from his time as a track and field athlete, granting him speed and endurance. He also uses his knowledge of ninja tactics and his agility in practical situations. Furthermore, he is known to use unconventional tools such as cat toys and small contraptions in his fight for survival. His reflexes and never-give-up attitude, inherited from his athletic days, are key assets he brings to the group.