Carly Meyers is an American agent who is dispatched to Japan as part of an investigation into the death of Ikuya Ogura. She is herself an Ajin, a demi-human possessing supernatural abilities. Physically, she is a young woman with blonde hair and red or brown eyes, and due to her professional role, she typically dresses in formal attire like a black suit and high heels.

Her personality is marked by a strong confidence in her abilities as an agent, and she is known to be quite clever and opinionated. This assertiveness has led to her being reprimanded on multiple occasions. She carries herself with an air of arrogance and can be outright rude, demonstrating a particular hostility towards certain individuals, such as Izumi Shimomura, whom she openly states she dislikes.

In the story, her primary role is that of an investigator, but her identity as an Ajin places her in a complex position within the world's power structures. Her key relationship is with Izumi Shimomura, with whom she shares a mutual hostility. While both work in similar professions and may have an unspoken understanding of the need to hide their Ajin nature to avoid being turned over to the government, they are ultimately enemies.

As an Ajin, Carly possesses several notable abilities. She is immortal and can fully regenerate from any fatal wound, reviving herself after being killed. She also demonstrates a high level of control over her Invisible Black Matter, allowing her to summon a Black Ghost or IBM that obeys her commands. This entity is hostile to anyone other than Carly and has a distinctive irregular-shaped head. It is assumed, though not demonstrated in the series, that she can also use the paralyzing scream common to her species. Her background as an agent also suggests she is skilled in interrogation and torture methods, such as using drugs to extract information.