Nico Hirata is a vampire serving as leader of the Vampire Council and a night school teacher. She possesses a relatively tall, slender build, distinctive red hair partially styled in a bun that consistently obscures the left side of her face, notable yellow eyes, prominent lips, and earrings in each ear. Her typical attire consists of a dark suit over a plain white shirt, matching pants, high heels, and no socks; she wore a simple white top and tight short skirt for Halloween. Like other vampires, she has fangs, though her entire mouth transforms into rows of sharp teeth during emotional instability or rage. Generally level-headed and acting as her group's representative, Nico expresses strong interest in romance topics, enjoys alcohol, and places high value on "dignity," while disliking lewd discussions. She engages in friendly rivalry, taking particular pride in her popularity. Despite claims otherwise, she harbors a violent side emerging in extreme anger. She avoids killing, preferring non-lethal resolutions, but will employ lethal force if sufficiently provoked or justified. Fundamentally supportive and forgiving, Nico actively encourages others' well-being and relationships, exemplified by her support for Kou and Nazuna's journey. She demonstrates deep care for her students, mentoring individuals like Lira Echigo. Her forgiveness is evident in her lack of resentment toward Anko Uguisu, who previously shot her in the head and killed other vampires. Nico also exhibits specific fondness for male students developing crushes on her; she rejects them when young but enjoys their return years later as mature adults. As a vampire, Nico possesses standard abilities: immortality, superhuman speed, strength, durability, levitation, and phasing through solid objects. She exhibits accelerated regenerative healing beyond human limits and a supernatural charm. While not the most experienced combatant among vampires, she held her own in a physical confrontation with the stronger Nazuna Nanakusa; her combat effectiveness is limited by her lack of extensive fighting experience. Nico maintains close friendships with fellow vampires Kabura Honda, Seri Kikiyou, Midori Kohakobe, and Hatsuka Suzushiro. She has mentored students including Kyouko Mejiro (later the vampire hunter Anko Uguisu), Nazuna Nanakusa, and Kou Yamori. Her relationship with Kou evolved from initially viewing him as a potential threat to humans' vampire awareness—suggesting he befriend vampires or be eliminated—to eventually supporting him as a former student and friend, albeit with periods of temporary enmity. She advised Kou during his intervention to prevent Anko Uguisu's suicide, prompting discussions about the ethics of saving someone determined to die. Appearing as the fourth vampire in the series, Nico was the first to propose integrating Kou into vampire society. Her background involves overseeing the Vampire Council and navigating complex group and human dynamics. She participates in key events, supporting Kou and Nazuna's evolving relationship, mediating vampire conflicts, and engaging in philosophical debates about human-vampire coexistence. Her development centers on balancing leadership responsibilities with personal connections, often serving as a stabilizing influence during tensions.