Karin Hanazono is the central protagonist of her story. She is introduced as a young, lonely middle school student who has faced significant hardship from an early age. Orphaned as a child, she was raised by an aunt who frequently scolded her for her poor academic performance and lack of athletic ability, leaving Karin feeling inadequate and isolated. Her only emotional support had been her beloved pet cat, Shii-chan, whose death several months before the story begins leaves her in a state of profound sadness.

Despite her difficult circumstances, Karin possesses an outgoing and determined personality, fiercely sticking up for her friends and loved ones when they are in danger. She is prone to exaggeration and can panic under pressure, which often means she requires help from those close to her to calm down. This trait is balanced by a strong sense of faith and trust in her companions, which can also lead her to be somewhat reckless, charging into battles without a clear plan. In the sequel series, it is revealed she has a secret interest in drawing boys' love manga.

Her motivation throughout the series is driven by a desire for connection and to understand her own mysterious past. The only memento she has of her deceased parents is a ring, which she soon discovers allows her to borrow the powers of a goddess. This discovery makes her a target for antagonists seeking that power, prompting her to move in with Kazune and Himeka Kujyou, who offer her protection. As the story progresses, her motivations shift from mere survival to protecting her new-found family, including her friends from Kujyou and later her own son, Suzune, who travels from the future to warn of a tragic fate she is determined to change.

Karin's role in the story is that of a magical heroine who must grow into her powers while unraveling the central mystery of her own identity. A key revelation is that Karin is not who she believes herself to be; she is actually the de-aged and memory-wiped form of Suzuka Kujyou, the wife of Professor Kazuto Kujyou and the mother of Himeka. The professor transformed her into a baby and renamed her Karin to protect her from his enemies, erasing all memories of her past life as his wife. This discovery fundamentally redefines her key relationships. Her relationship with Kazune is central, starting with friction due to his often condescending attitude, which she deems sexist. Over time, she develops deep feelings for him, though she initially believes they are one-sided because of his close bond with Himeka. It is eventually revealed that Kazune, a clone of her former husband, has known of her true identity since he was ten years old, and his feelings for her are genuine, leading to their eventual marriage. Her relationship with Himeka is a fast and genuine friendship, which later takes on a deeper complexity as she learns that Himeka is, in a sense, her daughter from a previous life.

Throughout the narrative, Karin undergoes significant development. She begins as a helpless, self-pitying girl and grows into a more confident individual capable of wielding divine power. When her original ring is destroyed, she receives a new one in the sequel series, Kamichama Karin Chu, which grants her the power of the goddess Aphrodite instead of her original power, which was associated with Athena. She later loses her memory again in the sequel, but with help from her friends, she is able to recover it and continue her fight to change a tragic future. Her notable abilities are centered on her ring, which allows her to transform into a goddess, proclaiming "I am God!" when she does so. In her initial form, she channels the power of Athena, the Greek goddess of wisdom and war. In Kamichama Karin Chu, her new ring allows her to channel the power of Aphrodite, the goddess of love.