Megumi TAKANI

Hated her during the first few episodes she appeared in but she becomes very likeable as the series continues. 

Megumi hails from Aizu and is the only living member of the Takani family, who were famous doctors for many generations. The Takani family was noted for treating all patients equally, regardless of wealth or status. During the seige of Wakamatsu Castle, Megumi parents and older brothers went out to treat the battle wounded, leaving Megumi behind. During the chaos, her parents were killed and her brothers went missing. Young Megumi was left alone in the world and left Aizu.

Eventually, she came to be apprenticed under a doctor. However, the doctor had a connection to a shady merchant by the name of Takeda Kanryuu. The doctor knew how to make a special, highly addictive opium and soon many were addicted. Kanryuu distributed the opium that the doctor made and split the profits with him. However, the doctor was greedy and wanted all the profit for himself. A fight ensued, with the doctor losing his life in the end. 

As the doctor's apprentice, Megumi knew how to make the special opium and was taken captive by Kanryuu who used a band of spies he had hired, the Oniwabanshuu, to keep an eye on her and keep her from escaping. Thus, Megumi spent several years being forced to make the special opium for Kanryuu, until the day came for her to make her escape...