Mandalay is the hero name of Shino Sosaki, a professional hero and the field commander of the rescue-oriented team known as the Wild, Wild Pussycats. She was born into a family of paramedics and search-and-rescue workers, which instilled in her a strong sense of duty to protect others even before her Quirk manifested at the age of six. Her Quirk, Telepath, allows her to send telepathic messages directly into the minds of one or many people at once, though it does not grant her the ability to read thoughts or receive replies. This ability makes her an invaluable coordinator during emergencies, as she can relay information and commands across large distances in real time.

Personality-wise, Mandalay is calm, gentle, and caring, especially toward her young nephew, Kota Izumi. She is also known to have a playful, occasionally teasing side, poking fun at her teammates or the students under her care. Despite her warm demeanor, she is fiercely protective and willing to fight when necessary, demonstrating capable combat skills and agility against opponents such as Spinner. Her motivations stem from a genuine desire to save lives and guide the next generation of heroes, even when faced with personal challenges like Kota's resentment toward heroes after the loss of his parents. She balances understanding his pain with remaining a steadfast symbol of heroism.

In the story, Mandalay first appears when the Wild, Wild Pussycats are tasked with training the students of U.A. High School during a summer training camp. She takes charge of communications and coordination when the League of Villains attacks the camp, helping to organize the defense and evacuations. Later, she participates in larger conflicts such as the Paranormal Liberation War, continuing to serve as a reliable field leader. Her key relationships include her teammates—Pixie-Bob, Ragdoll, and Tiger—as well as Kota, whom she raises and supports as he gradually overcomes his trauma. Throughout the series, Mandalay's character develops from a supporting rescue specialist into a respected figure whose leadership and compassion leave a lasting impact on those around her. Her notable ability beyond her Quirk lies in her strategic mind and her unwavering commitment to her role as a hero dedicated to saving others.