"Datenshi-ron" is a manga series that explores themes of morality, identity, and the blurred lines between good and evil within a supernatural framework. The narrative centers around a young man named Ryu, who becomes entangled in a world of angels and demons after a tragic incident alters the course of his life. Ryu discovers he possesses a unique ability to summon and control demons, a power that draws the attention of both celestial and infernal forces.

The story unfolds as Ryu is approached by a mysterious organization known as the "Order of the Fallen," which seeks to recruit him for their cause. The Order aims to maintain balance between the human world and the supernatural realms, but their methods often involve morally ambiguous decisions. Ryu is paired with a fallen angel named Lilith, who serves as his guide and protector. Lilith, once a high-ranking angel, was cast out of heaven for her defiance and now harbors a deep resentment toward both heaven and hell. Her complex relationship with Ryu becomes a focal point of the narrative, as their bond evolves from one of necessity to mutual understanding and trust.

As Ryu delves deeper into the supernatural world, he encounters various factions vying for control, including rogue demons, renegade angels, and human cults seeking to exploit supernatural powers for their own gain. The series introduces a diverse cast of characters, each with their own motivations and backstories, such as Gabriel, a stoic angel tasked with monitoring Ryu, and Asmodeus, a cunning demon who seeks to manipulate Ryu for his own agenda. These interactions highlight the moral gray areas that define the series, as characters often operate in shades of ambiguity rather than clear-cut heroism or villainy.

The plot is driven by Ryu's internal struggle to reconcile his humanity with his growing powers and the responsibilities thrust upon him. His journey is marked by intense battles, philosophical dilemmas, and moments of introspection as he grapples with questions of free will, destiny, and the nature of good and evil. The series balances action-packed sequences with quieter, character-driven moments, creating a narrative that is both engaging and thought-provoking.

"Datenshi-ron" also explores the concept of redemption, particularly through Lilith's arc as she seeks to atone for her past sins while navigating her complicated feelings toward Ryu and the world she once belonged to. The interplay between the human and supernatural realms serves as a backdrop for the characters' personal growth and the overarching conflict that threatens to disrupt the fragile balance between heaven, hell, and earth. The manga's intricate plot and morally complex characters make it a compelling exploration of the supernatural genre.