Karan is the mother of the protagonist, Shion, and resides in the dystopian city of No. 6. Her background includes an association with the original founders of the city, though the specific nature of her role during its establishment is not detailed. In her younger years, as seen in an old photograph, she had very short hair. At the start of the story, she lives with Shion in the city's privileged Chronos district but is later forcibly relocated to the outer wasteland known as Lost Town following her son's arrest.

In Lost Town, Karan demonstrates her resilience and work ethic by opening a small bakery, a craft at which she is exceptionally skilled. Her personality is characterized by a warm, happy, and gentle nature. She holds a deep-seated hatred for violence and refuses to associate with those who employ it. This principle leads her to reject an invitation from Yoming to join a rebel group, as she perceives the malice within him to be no different from that of the oppressive government she despises, showing her moral conviction even in the face of injustice. Despite the government’s hostile actions, including attempting to take her son, Karan remains outwardly submissive to the authorities, more focused on survival and the well-being of her family than on direct confrontation.

Her primary motivation throughout the story is the safety and happiness of her son, Shion, whom she raised single-handedly and shares a close, loving bond with. When Shion is captured and taken away, she is devastated, but finds relief through written messages delivered by Nezumi's trained rats, which inform her of his safety in the Western District. While Shion is away, her driving purpose becomes maintaining her bakery and waiting patiently for his return. This patience and quiet strength are emblematic of her character.

Karan's key relationships outside of her son include significant men in her past. Rikiga, an information broker, was once a journalist who wrote about her baked goods; they became very close, and he proposed a relationship, but she rejected him. Despite the passage of time, Rikiga still holds deep, unrequited feelings for her. Another figure, Yoming, also shows a romantic interest in her, hinting at a desire for a relationship, and frequently sends his niece to her bakery for food. She notably refuses Yoming's political invitation, further defining her independence from his ideologies.

While Karan does not undergo a dramatic personal transformation, her role in the story develops as she transitions from a resident of Chronos to a survivor in Lost Town. She creates a crucial, quiet link between Shion and the outside world by using Nezumi's rats as messengers, which is her primary way of maintaining hope. She is also revealed to have been present at the founding of No. 6, a historical connection that places her at the periphery of the city's deepest secrets. As a supporting character, her development is subtle, defined by her steadfast endurance and her continued faith in the original utopian ideals of the city, despite its corruption.

In terms of notable abilities, Karan possesses no combat or supernatural powers. Her strengths are domestic and personal. She is an exceptionally gifted baker and cook, a skill that serves as her livelihood. She also has a formidable work ethic, rising early each morning to prepare the day's bread and maintaining a strict schedule, indicating a resilience and inner strength that belies her calm and gentle exterior.