Mei Higurashi, biological daughter of Sōta Higurashi and Moe Higurashi, grows up in the modern era with her adoptive older sister Towa Higurashi. She is Moroha's maternal cousin and Kagome Higurashi's biological niece. Mei possesses long brown hair, brown eyes, and a warm skin tone, typically dressed in light pink shirts, dark purple vests, pink skirts, and Mary Jane shoes, shifting to coats and boots in winter.

Kind, optimistic, and gentle, she often smiles with warmth mirroring her mother and sister. Smart, honest, and talented, she occasionally displays shyness and naïveté. Her discomfort with violence leads her to plead with Towa to avoid fights. Key events include being taken hostage by bullies targeting Towa—where she first witnessed Towa's demonic abilities, sparking lasting admiration—and temporary possession by the minor demon Hitōkon, which drove her to attack family until Setsuna subdued her with sleeping powder.

Mei cherishes deep bonds, especially with Towa, whom she views protectively and loves profoundly. She affectionately calls Towa, Setsuna, and Moroha her "three older sisters," showing warmth toward Setsuna despite initial coldness and sharing mutual respect and cousinly affection with Moroha. Supportive scenes feature her welcoming Moe home from an orchestra tour with an apple, encountering Osamu Kirin at Haneda Airport, and noting escalating supernatural disturbances in her neighborhood, like frequent sirens. Once, she and her friends faced a threatening crow flock, unknowingly saved by Kirin. At the Sacred Tree of Ages, she emotionally implored Towa, Setsuna, and Moroha to promise their return to the modern era, underscoring her attachment.

Amid rising conflicts, Mei remains a grounding presence for her half-demon sisters, embodying ordinary human resilience. She expresses excitement about their adventures, attends events like Moe's concerts, and upholds her role as a symbol of familial stability.