Takani Megumi first appears in the series, both in the anime and the manga, immediately after the brief Jin-e arc. Fleeing from the Yakuza henchmen of an up-and-coming industrialist named Takeda Kanryuu, she encounters Kenshin and Sanosuke and appeals to them for help. Kenshin being Kenshin, he lends his assistance first and asks questions later. The story that unfolds reveals that this beautiful woman has a dark past but the potential for a bright future -- if she can escape her tormentor. As it turns out, her medical training goes a long way toward securing her a place in the lives of those who spend time at the Kamiya Kasshin Ryuu dojo. Her personality... not so much. Though her heart is kind, her tongue is sharp, quickly earning her the nickname "Kitsune-onna" -- fox woman.
She likes to tease people and has some interest in Kenshin, which Kaoru does not like at all. When she first appears, she seems cold-hearted and selfish, but later on we see her true self, a young woman who is lost in the world, searching for her family and friends. Megumi usually acts stouthearted, but she is actually just trying to hide her loneliness and the guilt she holds in her heart. She blames herself for the spreading of a new type of opium, and the deaths the opium caused. Her family was prestigious in the medical field for generations. They treated all their patients, disregarding any class difference. During the Aizusensou, all of them except a young Megumi went to the battlefield to fulfill their roles. As a result, Megumi's father was killed, and Megumi was separated from her mother and her two brothers. She was left alone in the world to fend for herself.
She was not heard from for several years but resurfaced as the assistant to an unnamed doctor who was working either with or for Kanryuu, manufacturing opium. Two years after that, the doctor was killed in a disagreement with Kanryuu over controlling the profits, and Megumi (who had learned the formulae from that doctor) was coerced into making the drug.