I was chosen to take care of the Great Sage but... Just what is it that he does all day?

On the day of their birth, two children were picked by the previous Great Sage. The first one, a boy, would be the next Great Sage and was stripped of his name. The second, a girl, was given the name Jessica and would be the Great Sage's care taker, in charge of all his needs. This is their daily life.