She is voiced by Hitomi Nabatame in the Japanese version of the anime, and by Anastasia Muñoz in the English version of the anime.
Mayu is a young adult woman with a tall and slim build, fair skin, and sharp, light brown eyes. Additionally, she has a beauty-mark under her left eye. She has long, straight, light brown hair with free-falling bangs covering most of her forehead, which she wears in different styles. At school, she keeps it tied into a ponytail at the back. When at home or during other occasions, she keeps her hair down, sometimes with a piece of her hair tied into a bun at the back. It is later seen that towards the end of the series, Mayu cuts her hair to about nape-length.
She is depicted as generally good-humored but sometimes aggressive—when Kyo attempts to leave class on Valentine's Day, she stops him at the door with a folder in his face and threatens to dye his hair black instead of orange, and once breaks up a fight between Haru and Kyo by dumping a bucket of water over them; she once demanded as a joke that.
Her parents, who worry about Shiraki being unmarried, run a bookstore where she sometimes helps out.
Shiraki is best friends with Kana, Hatori's former fiancée, and through her met Hatori, Shigure, and Ayame Sohma two years before the series begins. While Shiraki was attracted to Hatori, she was glad that Kana and Hatori were happy together. She dated Shigure for a month before breaking up, partly because Shigure was distant and partly because she was only dating him to alleviate her loneliness. She was at a loss when Kana and Hatori broke up, because Hatori had erased Kana's memory of the engagement. Shiraki still has feelings for Hatori, but resents Shigure's continuing interference in her life, even when it brings her closer to Hatori.
In the final chapter, Shiraki and Hatori are shown as a couple, with Hatori inviting her on an Okinawa vacation.
- She doesn't appears in 2001 Anime.
- Takaya said in an author's note that Shiraki is "possibly sad" that she is a woman and "secretly insecure of how tall she is," but since Hatori Soma is tall too, they "might look pretty good together as a tall couple."
- Her Japanese Voice Actress, Hitomi Nabatame also voices Rokumon from Rin-ne, Margery Daw from Shakugan no Shana and Saki from Pokémon.
- Her English Voice Actress, Anastasia Muñoz also voices Gracia Hughes from Fullmetal Alchemist: Brotherhood, Sucy Manbavaran from Little Witch Academia, Usami from Danganronpa: The Animation through Danganronpa 3: The End of Hope's Peak High School - Future Arc, Mira Naigus from Soul Eater Not! and Koko Hekmatyar from Jormungand.