Maguro Kurokami is the eldest child of Kajiki Kurokami and the older brother of Kujira and Medaka Kurokami. He is a former student of Class 13 at Hakoniwa Academy and was once a member of the Flask Plan's Thirteen Party, where he was given the project name Magician. At the time of the main story, he serves as the manager of Ghost Babel, the academy's old school building.

In terms of appearance, Maguro has long, waist-length purple hair with two distinctive ahoge (cowlicks), a style very similar to that of his younger sister, Medaka. His typical attire includes a purple shirt, violet wristbands, a necklace with a cross, and green pants with a belt decorated by a skull and crossbones. His eye color is red.

Maguro's personality is defined by a striking contrast between his flamboyant, often perverted demeanor and his razor-sharp perceptiveness. He is generally cheerful and lighthearted, but can become gravely serious when a situation requires it. His most prominent and obsessive trait is his love for his two younger sisters, Kujira and Medaka, though his obsessive affection is not something his sisters appreciate. Despite his goofy and teasing nature, especially towards Zenkichi Hitoyoshi, Maguro possesses a highly analytical mind. He is able to quickly understand complex problems and formulate effective countermeasures, often delivering his insights under the guise of jokes.

Maguro's motivations are deeply rooted in his family, particularly his search for his sister Kujira. He awakened his Abnormality while searching for her and later enlarged the Kurokami Group, a powerful financial conglomerate, to further this goal. He enrolled in Hakoniwa Academy and joined the Flask Plan as part of this same search. During his time in the Flask Plan, he became fascinated with a fellow member, Oudo Miyakonojou, to the point of temporarily forgetting his original goal. When his efforts to find Kujira proved fruitless, he chose to leave the Flask Plan. This departure came at a great physical cost, as the plan had taken samples of his organs, leaving him missing his left kidney, twenty percent of his heart, fifty percent of his liver, seventy-five percent of his stomach, and several arteries and veins. These physical injuries and the subsequent damage to his health forced him to drop out of school and take up management of Ghost Babel.

Maguro plays a significant role as a mentor and strategist. He recognizes Zenkichi Hitoyoshi as a positive influence on Medaka and initially asks him to remain by her side and protect her, though he later regrets placing such a burden on a freshman and decides to help Zenkichi improve himself instead. He is highly perceptive regarding the relationships and potential of those around him. Maguro was also a member of Misogi Kumagawa's Student Council during middle school, holding the position of Secretary, which ties him to some of the academy's most powerful figures.

His key relationships are centered on his family. He is the overprotective and obsessive older brother of Medaka and Kujira. He also has a noted relationship with Oudo Miyakonojou, whom he was once fascinated by. His dynamic with Zenkichi Hitoyoshi evolves from teasing to a genuine, if unorthodox, mentorship.

Maguro's most notable ability is his Abnormality called Analysis. This skill allows him to intuitively and automatically analyze and understand anything he encounters. He is a flawless analyst, trainer, and strategist. With just a hug and a punch, he was able to determine all of Medaka's physical statistics. More importantly, Analysis enables him to understand the mechanics of other Abnormalities and develop the most suitable methods to bring out the greatest potential in an individual. This ability makes him an exceptional manager and trainer who can nurture the hidden potential of others, directly contributing to his role at Ghost Babel. His skill Analysis is powerful enough that it was later copied by Medaka using her own ability, The End.