"Shuriken Tonma" is a manga series set in a fictionalized version of Japan's Edo period, blending historical elements with supernatural and martial arts themes. The story centers around Tonma, a young ninja from the Koga clan, who wields a unique shuriken known as the "Tonma Shuriken." This weapon is imbued with mystical powers, allowing Tonma to combat malevolent spirits and supernatural threats. The narrative begins with Tonma's quest to avenge his father, who was killed by a powerful demon. Along the way, Tonma encounters various allies and adversaries, including other ninja clans, yokai (supernatural creatures), and corrupt samurai.

The plot unfolds as Tonma uncovers a larger conspiracy involving the resurgence of ancient demons and their influence over human affairs. These demons, led by a malevolent entity known as Orochi, seek to plunge the world into chaos. Tonma's journey takes him across feudal Japan, where he battles both physical and spiritual enemies while honing his skills as a ninja. His encounters often involve intricate strategies and the use of his shuriken's unique abilities, which evolve as the story progresses.

Key characters include Tonma's mentor, an elderly ninja who provides guidance and training, and a female ninja named Sayaka, who becomes a close ally and confidante. The series also features a range of antagonists, from rival ninja clans with their own agendas to powerful yokai serving Orochi. The interplay between these characters drives the narrative forward, with alliances and betrayals shaping the course of Tonma's journey.

The manga explores themes of loyalty, honor, and the struggle between good and evil, set against the backdrop of a richly detailed historical and supernatural world. The action is punctuated by moments of introspection and character development, as Tonma grapples with the weight of his mission and the moral complexities of his path. The story builds toward a climactic confrontation with Orochi, where Tonma must harness all his skills and the power of his shuriken to prevent the demon's plans from coming to fruition.