Haruka Kaibara is an exorcist who appears in the anime adaptation of Twin Star Exorcists. She is distinguishable by her short purple hair and purple eyes, with a notable mole located underneath her right eye. This appearance contrasts with her counterpart in the original manga, where her face is not clearly shown and she instead has very long hair tied in a ponytail.

Before her introduction to the main setting, Haruka spent several years studying abroad in Europe. During this time, she pursued the study of art, which indicates a creative and cultured side to her character beyond her duties as an exorcist. Upon returning to Japan, she joins the Seika Dormitory and works at a local preschool, demonstrating a willingness to engage with the community and care for children.

In terms of personality, Haruka is depicted as proactive and confident, particularly in her personal life. She takes the initiative in her relationships, a trait most clearly seen when she begins dating her fellow exorcist, Ryogo Nagitsuji. Their relationship is set up by a mutual friend, Fushihara Toru, who encourages them to go on a date. From the outset, Haruka is often the one who takes the lead during their outings. This assertive yet warm personality makes her a complement to Ryogo, who is characterized as being more formal and dedicated entirely to his work. Haruka represents a life outside of constant exorcism, which is a central theme for her narrative.

Her primary role in the story is to provide a different perspective on the world of exorcists, shifting the focus away from the elite and prophesied heroes to the ordinary individuals who balance their supernatural duties with regular lives. For Haruka, being an exorcist is a job, not her entire identity. Her romance with Ryogo explores the challenges and possibilities of maintaining a personal relationship while fighting against malevolent forces. The story questions whether two exorcists can build a future together while defending the world.

Her key relationship is, without a doubt, with Ryogo Nagitsuji. She falls in love with him, and their relationship progresses steadily after their first date. In a significant development, Ryogo proposes to Haruka while the children at the preschool where she works are taking a nap. He promises to protect her smile, and she accepts his proposal on the condition that she can do the same for him, establishing a partnership of mutual protection and care. By the conclusion of the anime, they are married, and she takes his surname, becoming Haruka Nagitsuji.

While specific details of her exorcist abilities are not extensively detailed, it is established that she is a fully qualified exorcist of the Mainland. She is capable of entering Magano and fighting Kegare, the show's primary antagonists. However, her skills are portrayed as being on a more standard, non-elite level compared to characters like the Twin Stars. Her true development is not in combat prowess but in her personal journey toward finding happiness and a reason to protect others. Her friend Fushihara believed that in order to be the best exorcist one can be, there must be something special to protect. For Haruka, as she discovers through her relationship with Ryogo, that something becomes the bond she shares with him.