One Piece: King of the World - Chapter 91 - : Subtle Hint

“Keep it in your mouth… Swallow it… Baby, be good…“

The Revered Master, Yu Yan, known as the number one in the cultivation world, waited for sixteen thousand years, and finally took in a disciple. He taught her carefully, and took care of her diligently. He watched her as she slowly grew stronger as she comprehended the laws, and just as she was about to soar into prominence… she died!

Liu Fang, a manager, died suddenly at work due to being too diligent.
She thought that she would turn into a wisp of dust and dissipate after her death, but she never imagined that – the new century, the new underworld, even if she became a soul, she would still be a worker!

Liu Fang has become a newcomer to the underworld Quick transmigration Department. In order to wait for a good reincarnation, she strived to accumulate merit and traveled into one world after another to repair the way of heaven.

- Description from Novelupdates