Niko Hirata is a vampire and a teacher at a night school, serving as a supporting character in the story. She stands out with a tall, slim build, red hair that she sometimes ties in a partial bun or wears loose, and yellow eyes. As a seasoned vampire, she moves easily within human society by working as the director of academic affairs at a night school, a role that lets her blend in while overseeing five thralls. Her background places her among a close circle of fellow vampires, including Kabura Honda, Seri Kikiyou, Midori Kohakobe, and Hatsuka Suzushiro, with whom she shares a long friendship. Niko is generally calm and level-headed, often acting as the voice of reason within her group. She has a strong interest in romantic gossip, enjoys drinking, and places great importance on maintaining dignity. While she dislikes lewd topics and tends to avoid killing, she possesses a hidden violent streak that emerges when she becomes extremely upset, revealing a full set of sharp teeth. Her motivations center on keeping the human world unaware of vampires, which leads her to initially plan to turn the protagonist Kou Yamori into a vampire as a way to minimize risk of exposure. Over time, however, she becomes more supportive of Kou and Nazuna Nanakusa, encouraging their journey and showing genuine care and compassion for her students, such as Lira Echigo. Her forgiving nature is evident when she bears no resentment toward Anko Uguisu, even after being shot in the head by her. Niko is often regarded as a leader among the vampire clique, taking the lead in many situations while remaining diligent and caring toward those close to her. As a vampire, she possesses immortality and a range of supernatural abilities, including levitation, the ability to phase through solid objects, superhuman speed, strength, and rapid regeneration. She also has a natural vampiric charm that allows her to influence others and gain popularity among humans, helping her expand her circle of followers. Throughout the narrative, Niko develops from a calculating figure into a nurturing mentor, balancing her authoritative presence with deep concern for the well-being of both her vampire peers and her human students.