"Sentō Jōsai Masurawo" is a manga series that blends elements of action, fantasy, and historical intrigue. The narrative centers on Masurawo, a skilled warrior from a bygone era who is resurrected in modern-day Japan to protect the country from supernatural threats. Masurawo's resurrection is tied to a mystical artifact known as the "Jōsai," a powerful relic that binds him to the will of its current guardian, a young woman named Aoi. Together, they form an unlikely partnership to combat malevolent entities known as "Kegare," which seek to corrupt and destroy the world.

The story unfolds as Masurawo and Aoi navigate a series of escalating battles against increasingly powerful Kegare, each encounter revealing more about the origins of the Jōsai and Masurawo's past. Masurawo's combat prowess and ancient techniques are juxtaposed with the modern world, creating a dynamic interplay between tradition and contemporary society. Aoi, while initially inexperienced, grows into her role as a guardian, learning to harness the Jōsai's power and support Masurawo in their shared mission.

As the plot progresses, the duo uncovers a deeper conspiracy involving the Kegare and their connection to the Jōsai. The narrative explores themes of duty, sacrifice, and the clash between old and new values. Supporting characters, including other warriors and guardians, are introduced, each contributing to the overarching conflict and providing additional layers to the story. The series balances intense action sequences with moments of character development, delving into the motivations and histories of both Masurawo and Aoi.

The manga's pacing is structured around episodic battles interspersed with revelations about the world's lore and the characters' backstories. The stakes rise as the true nature of the Kegare and the Jōsai's purpose are gradually unveiled, leading to a climactic confrontation that tests the resolve and abilities of Masurawo and Aoi. The series concludes with a resolution that ties together the central narrative threads while leaving room for potential future developments.