Nico is a tall, slender woman with red hair that she either ties partially in a bun or wears loose, with her hairstyle always covering the left side of her face. She has striking yellow eyes, noticeably full lips, and wears an earring on each ear.

Her typical attire consists of a dark suit paired with a plain white shirt and matching pants, giving her a professional yet stylish appearance. On Halloween, she opts for a more casual look with a simple white top and a tight, short skirt. Nico completes her outfits with high heels and never wears socks. Like other vampires, she has fangs, but when enraged, her entire mouth reveals a set of sharp teeth, emphasizing her volatile nature.

Nico is generally calm and level-headed, often serving as the voice of reason within her group. She is deeply interested in discussions about romance, enjoys drinking, and places great importance on maintaining dignity. Though she dislikes lewd topics, she often engages in lighthearted competition with her friends and Hatsuka, taking pride in her popularity and charm.

Despite her composed demeanor, Nico has a hidden violent streak that surfaces when she becomes extremely upset or angry. While she dislikes killing and tries to avoid violence, she is capable of doing so if necessary.

At her core, Nico is warm, friendly, and supportive, genuinely caring about those around her. She encourages Kou and Nazuna in their journey and shows great compassion toward her students, especially Lira Echigo. Her forgiving nature is evident when she bears no resentment toward Anko Uguisu, even after Anko killed and injured other vampires and shot Nico in the head.

Vampiric Abilities: As a vampire, Nico possesses immortality and a range of supernatural powers. She can levitate, phase through solid objects, and move at incredible speeds. Her physical strength and durability far exceed that of humans, and she can regenerate from injuries rapidly. In addition, Nico has a natural vampiric charm that allows her to subtly influence others, making her presence both captivating and intimidating when she wishes.