"Black Torch" is a supernatural action manga set in a world where humans coexist with spirits known as mononoke. The protagonist, Jiro Azuma, is a descendant of the ninja clan and possesses the unique ability to communicate with animals. After a chance encounter with a wounded mononoke named Ragou, Jiro forms a bond with the spirit, leading to their fusion. This fusion grants Jiro extraordinary powers but also draws the attention of the Bureau of Espionage, a government agency tasked with handling supernatural threats.

The Bureau recruits Jiro into their ranks, where he joins a team of agents who specialize in dealing with rogue mononoke and other supernatural phenomena. Among his teammates are Ichika Satomi, a skilled swordswoman, and Shiba, a mysterious and powerful agent. Together, they investigate and combat threats posed by rogue mononoke and a shadowy organization known as Saginuma, which seeks to exploit mononoke for their own nefarious purposes.

As the story progresses, Jiro learns more about the history and nature of mononoke, as well as the dark secrets surrounding the Bureau and its operations. The narrative explores themes of coexistence, loyalty, and the blurred lines between good and evil. Jiro's journey is marked by intense battles, personal growth, and the struggle to protect both the human and spirit worlds from destruction.

The manga balances action-packed sequences with moments of introspection, delving into the relationships between humans and mononoke, as well as the internal conflicts faced by the characters. The plot is driven by a mix of personal vendettas, political intrigue, and the overarching threat posed by Saginuma, culminating in a high-stakes confrontation that tests the limits of Jiro's abilities and resolve.