Nemuri Kayama, the Pro Hero Midnight, serves as a U.A. High School instructor teaching Modern Hero Art History. Her Quirk, Somnambulist, releases a sleep-inducing aroma from her skin, amplified by tools like whips and fans to spread the scent. Proximity and inhalation determine its potency, with heightened effects on males. To bypass costume restrictions on skin exposure, she dons a tearable ultra-thin suit for quick Quirk activation. Midnight’s origins trace back to her U.A. student days in *Vigilantes*, interning under His Purple Highness in her third year. There, she honed a theatrical yet empathetic hero style. Close bonds with classmates Shota Aizawa and Hizashi Yamada revealed her nurturing side, exemplified when she temporarily cared for a stray kitten Aizawa rescued. The loss of their friend Oboro Shirakumo during a mission deepened her commitment to safeguarding others. Balancing hero duties with education, she joined U.A.’s staff before Aizawa, persuading him to teach. Her playful, teasing personality shifted to sternness when her authority faced challenges or her age was noted. She orchestrated U.A. events like the Sports Festival, pushing students to blend creativity with resolve. During Final Exams, she assessed strategic adaptability, notably acknowledging Minoru Mineta’s clever exploitation of her tendencies during their clash. Midnight’s mentorship extended to guiding students in choosing hero identities. In the Paranormal Liberation War, she tasked Momo Yaoyorozu with a pivotal plan to incapacitate Gigantomachia, urging her to deploy sedatives despite legal boundaries. Ambushed by villains post-battle, she succumbed to injuries from Mr. Compress’s debris, her off-screen death starkly illustrating heroism’s risks and reshaping students’ views of their vocation. Her costume evolved from an initially provocative design—which spurred government attire reforms—to a functional dominatrix-inspired ensemble. The name “Nemuri Kayama” mirrors her Quirk: “Nemuri” (sleep) and “Kayama” (combining “fragrance” and “mountain”). In *Vigilantes*, she collaborated with vigilantes Koichi Hirose and Pop Step, even forming a pop group to revitalize a shopping district. These interactions showcased her adaptability in supporting unorthodox allies and balancing her bold hero persona with off-duty warmth. Midnight shaped hero society through education, regulatory shifts, and fostering future heroes. Her mix of tactical ingenuity, whimsical charm, and unwavering dedication left an indelible mark, while her death became a narrative catalyst, underscoring the fragile balance between heroism’s sacrifices and its enduring legacy.