Miniskirt Santa is a mysterious young woman who appears before Sakuta Azusagawa early in the university arc of the story. She is first encountered wearing an out-of-season miniskirt Santa Claus costume and introduces herself as Touko Kirishima, a popular anonymous internet singer who has recently gained widespread attention. She claims that she is going around distributing Puberty Syndrome, also called Adolescence Syndrome, as gifts to people, and she states that she is responsible for ten million cases of the phenomenon, including those affecting Uzuki Hirokawa and Ikumi Akagi. One of her most striking traits is that she is invisible to everyone except Sakuta; she does not appear in photographs or video recordings, making her existence uniquely enigmatic. Her personality is initially playful and cryptic, but beneath the surface she carries a strong sense of purpose linked to her real identity. That real identity is Nene Iwamizawa, a girl who is not actually the singer Touko Kirishima but who takes on that persona for reasons tied to her own experiences with Adolescence Syndrome. Her motivations revolve around the spread of the syndrome as a kind of gift, and later around the need to protect or resolve the true nature of the Touko Kirishima phenomenon. In the story, she serves as the central mystery of the university arc, driving Sakuta to investigate the connection between the online singer, the rumors surrounding Mai Sakurajima, and the growing number of Adolescence Syndrome cases. Her key relationship is with Sakuta, who becomes the only person able to interact with her directly. She also has a complex connection to Mai, as Mai is falsely accused of being Touko Kirishima, and Miniskirt Santa’s actions force Sakuta to navigate a web of lies and public scrutiny. Over the course of the narrative, she undergoes significant development as her true identity and reasons for appearing are revealed, shifting from an enigmatic, almost antagonistic figure into a sympathetic character whose actions stem from personal pain and a desire to give meaning to her own existence. Her most notable abilities include her selective invisibility—only Sakuta can see or hear her, and she cannot be captured by any recording device—as well as her apparent ability to cause or influence Adolescence Syndrome in others, which she describes as her gift. These traits place her firmly within the series' supernatural framework while tying her story to the series’ recurring theme of unseen emotional turmoil manifesting as visible phenomena.