Kikyou Zoldyck is the matriarch of the Zoldyck Family, the renowned line of assassins in the Hunter × Hunter series. She is the wife of Silva Zoldyck and the mother of their five children: Illumi, Milluki, Killua, Alluka, and Kalluto. Her origins lie outside the family's elite bloodline, as she originally comes from Meteor City, a junkyard settlement inhabited by outcasts.

In terms of appearance, Kikyou is a tall woman with a distinctive and ornate fashion sense. She typically wears an elaborate dress, often depicted as yellow or deep purple, adorned with lace. She completes her outfit with a matching hat decorated with roses and a feather. One of her most notable features is the electronic prosthetic that replaces one of her eyes, which serves as a reconnaissance device capable of scanning the extensive Zoldyck estate grounds. The lower part of her face and her neck are also wrapped in white bandages.

Kikyou possesses a highly excitable and neurotic personality, speaking with a characteristically high-pitched voice. Her demeanor is often described as being obsessed with a refined, courtly aesthetic. As an assassin, she is a skilled user of Nen, classified as a Manipulator. Her abilities, likely stemming from her background in the harsh environment of Meteor City, allow her to hold her own within a family of such formidable killers.

Her primary role in the story is that of an overbearing and possessive mother. She is deeply invested in the family trade, holding extremely high expectations for her children to become top-tier assassins. This is most evident in her relationship with her third son, Killua, whom she regards as the heir to the family business. She expresses overwhelming joy at his development as an assassin, even to the point of crying for a long time after he stabbed her, an act she interpreted as a sign of his growing independence and maturity. However, this affection is profoundly twisted. Her love is conditional and interwoven with a desire for control and a commitment to the family's brutal training methods.

Kikyou's relationships within the family are complex and often strained by their profession. She was brought into the Zoldyck family by Silva, who expected her to bear him strong children. She is shown to be a strict and unforgiving figure; on one occasion, she tortured a young butler with an electric whip for perceived negligence. When a young Killua grabbed the whip to stop her, he endured severe injuries to his hands as she did not relent. This event led him to stop calling her "mama". Her relationship with Killua is central to her characterization, as she represents the life and expectations he attempts to flee from. Her constant, high-pitched screaming whenever he leaves the estate further underscores her dramatic and obsessive nature. Kikyou ultimately stands as a primary enforcer of the Zoldyck family's will, embodying both the elegance and the inherent cruelty of the world of professional assassins.