TV-Series
Description
Kotaro Fuuma is the ancient and secretive leader of the Fuuma Village, a major power in the hidden ninja world of Nabari. He was born during the Edo period, over a hundred and twenty years before the events of the story, and was originally a human who could not accept the idea of dying without ever experiencing the full wisdom of the Shinrabanshou, the ultimate secret art. To pursue this goal, he abandoned his natural lifespan and spent decades mastering forbidden techniques and compiling knowledge. Over this time, he wrote nearly all the surviving texts on ninjutsu and the Shinrabanshou, establishing himself as the foremost scholar in all of Nabari, a title that masks his far more ruthless ambitions.

In personality, Fuuma presents a deliberately misleading facade. He is openly hedonistic, frequently claiming that his greatest desire is to use the Shinrabanshou to create a paradise where every woman in the world loves him. He surrounds himself almost entirely with female residents in his village and speaks in a light, boastful manner. Despite this, close associates such as Raimei Shimizu note that he is lying most of the time. Beneath this playful exterior, he is deeply calculating, manipulative, and utterly focused on his true goal. He maintains a sprawling network of spies within other ninja villages and operates with a patience that spans decades, always hiding his genuine intentions behind a mask of eccentricity.

His primary motivation is an obsessive desire to acquire the Shinrabanshou for himself and meet its female spirit, whom he calls Shinra. He longs to transcend human understanding and attain a state of godlike wisdom, viewing the Shinrabanshou not just as a tool of power but as the key to his own apotheosis. This single-minded pursuit governs all his decisions and makes him willing to sacrifice anyone, including his own allies, to achieve it.

Fuuma originally appears as a powerful but neutral scholar who is consulted by the Banten ninja for advice on how to remove the Shinrabanshou from Miharu Rokujou. However, his role shifts dramatically when he is unmasked as the story's primary antagonist. Ten years before the main plot, it was Fuuma who killed the young Miharu, forcing Miharu's mother, Asahi, to activate the Shinrabanshou to revive her son, thereby transferring the sacred art into him. This single act set the entire chain of events in motion. He later aligns himself with the Grey Wolves, betraying the trust of his own village, in a scheme to finally claim the Shinrabanshou for himself.

His key relationships are defined by this deception. He views Miharu as a mere vessel rather than a person. His relationship with Tobari Kumohira is one of deep, built-up animosity, culminating in Tobari becoming his killer. He maintains a master-servant dynamic with Raimei and the other members of Fuuma Village, many of whom sever their allegiance upon learning of his true nature. His only genuine emotional connection appears to be with the spirit of the Shinrabanshou itself.

His development traces the gradual removal of his mask. The story begins with what seems like a wise, untrustworthy, but ultimately helpful ally and reveals him to be the cold, precise mastermind who orchestrated the tragedy that started the entire conflict. This journey ends in his final confrontation. After absorbing a number of forbidden techniques, he is fatally stabbed by Tobari. His body, having been unnaturally sustained by jutsu for over a century, cannot withstand the damage and rapidly decays into a skeleton, leaving him dead.

Fuuma possesses a vast range of abilities. He is a master of transformation techniques, so skilled that no one knows his true appearance. He employs standard ninja skills such as nawajutsu and hengejutsu, but his most notable powers come from forbidden jutsu. By acquiring his own village's secret technique, Tenpenka, and the Iga village's kinjutsusho, Kira, he can assume the exact forms and abilities of other powerful ninja, such as the Kira-using leader of the Kairoshuu intelligence unit. His greatest weapon, however, is his accumulated knowledge and strategic patience, which he uses to remain hidden and pull the strings of the Nabari world for generations.