Shortly after birth, Fujimaru is snatched by an eagle, only to be rescued and adopted by the ninja Sasuke. This abduction severs ties to his biological mother, who never learns he survived. Raised in the Fūma ninja clan under Sasuke’s guidance, he endures intense ninjutsu training. This discipline sharpens his natural affinity for wind control, forging it into combat and evasion maneuvers. His signature techniques include conjuring illusory duplicates ("multiplication") and summoning swirling winds veiled by leaves to mask escapes ("leaves").

His core mission focuses on recovering the "Ryuen Book" or "Book of the Smoking Dragon," a scroll housing perilous techniques. Initially dispatched by his master Tasuke to retrieve it, Fujimaru is ambushed and falsely accused of destroying the scroll. Branded a "stray dog orphan" and exiled by Tasuke, he uncovers the burned scroll was a decoy—the authentic one still hidden. This betrayal redirects his purpose: he vows to secure the remaining scrolls alone, thwarting their misuse.

A pivotal clash erupts when Sasuke, obeying Fūma clan orders, confronts Fujimaru with lethal intent. During their duel, Sasuke feigns defeat and reveals Fujimaru’s mother lives and seeks him. This revelation intertwines his quest: reunite with his mother and safeguard the scrolls. Post-battle, Sasuke vanishes, leaving Fujimaru solitary.

Adversaries like Japusai—a fire-wielding master bent on world domination—hound him, embodying unadulterated malice. Later threats emerge, including the Nanban ninjas and the ninja Haguro, relentlessly testing his resolve and skills.

Fujimaru evolves from a naive disciple into a self-reliant strategist. His initial clan-bound duty expands to include the emotional pursuit of his mother, especially after exile. Ultimately, he achieves both goals: locating his mother and securing the Ryuen scroll. Recognizing its catastrophic potential, particularly under Japusai’s pursuit, he destroys the scroll to erase its threat.