Mokou Fujiwara was formerly an ordinary human, but she became an immortal being after drinking the Hourai Elixir about 1300 years ago. Now she is never able to die, though she still feels the pain of injuries as normal. Mokou is a loner by nature and chooses not to socialize with humans or youkai. She escorts lost humans she finds within the Bamboo Forest of the Lost, giving herself a job similar to that of a bamboo forest guide, and even then after escorting between Human Village and Eientei, she departs without saying a word. Nevertheless, to those whom she's acquainted with, she speaks bluntly and with lively personality.