Na Seungri, more commonly known by her given name Kagura, is a main protagonist in the anime Azumanga Daioh who joins the core group of friends during their second year of high school. She first appears as a background character in the first year, placed in Minamo Kurosawa's class, and catches attention during the school athletics festival when she narrowly loses a race to the naturally gifted Sakaki. This defeat sparks a one-sided rivalry in her mind, though Sakaki does not even remember the event. At the start of the second year, her eccentric homeroom teacher Yukari Tanizaki transfers her into the class specifically to strengthen the class's performance in sports competitions.

Kagura is defined by her tomboyish, energetic, and highly competitive personality. She devotes most of her time to the school swim team, training year-round under the guidance of Nyamo, which gives her a pronounced tan line during the summer months. Despite her athletic drive, she possesses a soft and sentimental side that she sometimes tries to conceal. She is deeply loyal to her friends and feels genuine remorse when she makes mistakes, such as crying after accidentally tackling the younger Chiyo Mihama during a sports festival. Her primary motivation is to prove her athletic ability and to surpass Sakaki, whom she admires for her effortless talent. However, her competitive nature is balanced by a caring instinct, and she often protects Sakaki by scaring away the stray cats that bite her. Academically, she is a poor student and bonds with Tomo Takino and Ayumu Osaka Kasuga over their shared lack of studiousness, forming a trio humorously called the Knuckleheads.

Her role in the story is that of a late addition to the established friend group, providing a new dynamic of athletic rivalry and heartfelt camaraderie. Key relationships include her friendly but one-sided rivalry with Sakaki, which gradually evolves into a genuine friendship as she supports Sakaki in overcoming her fear of cats and helps care for an injured kitten. She shares a close, sometimes volatile friendship with Tomo due to their similar competitive spirits, and a more easygoing bond with Osaka, whose eccentric comments contrast with Kagura's grounded nature. She holds great respect for her former teacher and swim coach Nyamo, calling her Coach, and reacts with open disgust toward the lecherous teacher Kimura. Over the course of the series, Kagura matures from a competitive newcomer into a more empathetic and supportive friend, while still maintaining her dedication to athletics. Her notable abilities include exceptional physical prowess, particularly in swimming and stamina-based events, though she often falls short of Sakaki in pure speed and natural talent. By graduation, she expresses her ambition to become a professional swimmer, with Chiyo expressing hope that she will reach the national level.