Kanryu Takeda is a former opium dealer and a primary antagonist encountered during the events in Tokyo. His background is rooted in a deep-seated desire for wealth and power, having risen from an impoverished childhood by any means necessary. He established a lucrative and illegal business trafficking a new, potent form of opium known as Spider's Web. To produce this drug, he forced the skilled doctor Takani Megumi to work for him, having killed her predecessor for refusing to continue. His ultimate goal was to use the immense profits from his drug trade to purchase advanced Western weaponry, such as the Gatling gun, and become a powerful arms dealer, believing this would make him the most dominant force in the world.

In terms of personality, Takeda presents a deceptive facade. He typically appears composed, speaking politely to others with a serene smile and his eyes often closed. This mask, however, conceals a truly vile and narcissistic nature. He holds a profound contempt for everyone around him and possesses a quick, violent temper that emerges when he is insulted or his superiority is challenged. Takeda has absolutely no regard for human life; he coldly orders the assassination of subordinates for their failures and displays sadistic pleasure in the suffering of others. He is fundamentally a coward who relies entirely on his wealth and hired muscle for protection. When confronted by a genuine threat he cannot immediately buy off, he becomes panicked and tries to escape. His worldview is entirely materialistic, leading him to be incapable of understanding concepts like honor or loyalty, as he cannot comprehend why anyone would act without a monetary incentive.

Takeda's primary role in the story is as the instigator of the conflict that brings Shinomori Aoshi and his Oniwabanshū to Tokyo. He hires Aoshi and his four elite subordinates, along with a private army of around sixty men, as his personal bodyguards and enforcers to protect his opium operation. His relationship with these hired fighters is purely transactional; he believes his money gives him absolute control over them, a misconception that ultimately proves fatal to his plans. He looks down on Aoshi and the others, seeing them as mere tools. His most significant relationship is with Takani Megumi, whom he cruelly imprisons and exploits to manufacture opium, holding her against her will. When Kenshin and his allies storm his mansion to rescue her, Takeda serves as the final obstacle they must overcome.

Throughout his encounter with Kenshin, Takeda shows little capacity for change or redemption. He remains arrogant and confident in the power of his wealth until the very end. His most notable development occurs much later in the Hokkaido arc, where he is revealed to have survived his imprisonment. He adapts to his circumstances, using his cunning to escape prison and becoming a shadowy merchant distributing swords, still chasing his ambitions but with a somewhat more pragmatic, if still self-serving, approach.

In terms of abilities, Takeda is not a physical fighter; he is described as having little to no physical strength or stamina. His true skills lie in his cunning, his talent for making money, and his complete lack of scruples. His most notable weapon is a powerful Gatling gun, a rapid-firing weapon that he relies upon to massacre anyone who threatens him, including his own hired swordsmen when they outlive their usefulness. He uses this weapon as a great equalizer against supremely skilled fighters like Kenshin. Ultimately, his capabilities are defined by his financial power, his network of hired thugs, and his willingness to use overwhelming, modern firepower, not by any martial prowess of his own.