Haruka Luciela investigates paranormal cases involving demonic entities called Nights for the IATO's Chemistry Division. Assigned to Kamaya City, she collaborates with the local police, including Shingo Sumeragi, to research supernatural phenomena. She discovers a link between Matoi Sumeragi's sudden exorcist powers and incidents at Tenman Shrine, leading her to establish close contact with Matoi and Yuma Kusanagi to gather information on the interdimensional conflict involving higher-dimensional beings and evil spirits.

Her appearance features green eyes, blonde hair cut to neck length, and an adult stature. She typically wears cool shades, a low-cut suit, pantyhose, high heels, and a choker, creating a noticeable presence. This striking look often draws attention, particularly from male characters like Hideo Tezuka.

Personality-wise, she demonstrates a strong sense of duty and perfectionism, upholding high moral standards in her work. Her birthday is July 31, placing her under the Leo zodiac sign. Though mission-focused, she develops protective instincts toward Matoi and Yuma, aiming to shield them from supernatural threats despite her primary investigative role.

Her background reveals no familial details, with one source indicating French nationality. She operates with a blend of professional detachment and genuine concern, balancing her goal of understanding the Nights with a growing commitment to the safety of those involved in exorcist activities.