"Bible Black Origins" is a prequel to the "Bible Black" series, delving into the events that set the stage for the dark and occult-themed narrative. The story centers around the origins of the cursed grimoire known as the Bible Black and its influence on the lives of those who encounter it. The series explores the rise of a secretive occult group at a high school, led by a charismatic yet sinister figure named Minase Reika. Her ambition to harness forbidden magic drives the plot, as she seeks to unlock the grimoire's power to achieve her goals.

The narrative unfolds through the perspective of several characters, including students and faculty, who become entangled in the occult activities. As the group delves deeper into dark rituals, the consequences of their actions spiral out of control, leading to moral decay, psychological torment, and supernatural horrors. The grimoire's malevolent influence corrupts those who use it, blurring the lines between reality and nightmare. Themes of power, obsession, and the consequences of forbidden knowledge are central to the story.

Key characters include Minase Reika, whose descent into darkness serves as the catalyst for the events, and her followers, who are drawn into her schemes. The series also introduces individuals who resist the occult's pull, attempting to uncover the truth behind the grimoire and its origins. The interplay between these characters creates a tense and foreboding atmosphere, as the narrative builds toward the inevitable clash between those seeking to wield the grimoire's power and those striving to stop its spread.

The plot is structured around a series of interconnected events, revealing the gradual escalation of the occult group's activities and the growing threat posed by the grimoire. The story maintains a focus on the psychological and supernatural elements, emphasizing the destructive impact of the characters' choices. "Bible Black Origins" serves as a foundation for the broader "Bible Black" universe, providing context for the events and themes explored in subsequent installments.