Black-haired high school girl Misa Kuroi is, beneath her ordinary student appearance, a powerful young witch who wields black magic. Having advanced from her middle school days into high school, she continues to move through different schools, using her occult knowledge to confront supernatural threats, punish those who commit evil, and expose the darkness hidden in human hearts. A long black-haired beauty with a frog-hand-shaped birthmark on her neck, the mark of her contract with a demon, Misa is both a ruthless punisher who shows no mercy to criminals and a compassionate figure who helps those caught in terrible situations. She is skilled in martial arts, can dislocate her jaw to contort her face into a grotesque expression, and can summon and command demons such as Astaroth and Shax. She often works part-time as a fortune-teller and is sometimes employed at her family's clinic.

Eko Eko Azarak II continues the storyline from the original Eko Eko Azarak and its immediate sequel Majo Kuroi Misa. The setting shifts to high school, where Misa encounters fresh waves of bizarre incidents, occult conspiracies, and malevolent forces. Each episode presents a self-contained horror narrative in which Misa applies her magical expertise to solve mysteries, break curses, and confront both human villains and supernatural entities. The tone balances the everyday life of a student with the dark, brutal world of black magic, where Misa sometimes acts as an aggressor and other times as a victim of circumstances beyond her control. As the series progresses, she increasingly takes on the role of a dark heroine who stands against greater evils. The final story arc, published under the title Shin Kuro Majutsu Eko Eko Azarak, brings the series to a close with a climactic confrontation that resolves the lingering threads of Misa's journey. Typical narrative arcs involve Misa transferring to a new school, identifying the source of a supernatural disturbance, and deploying her spells and knowledge to eliminate the threat, often with morally ambiguous consequences that leave the line between good and evil blurred.