In the past, twins were born, but it was believed that having more than one baby at a time brought bad luck. Sadly, the female twin passed away after being crushed by a millstone. Her body was buried beneath a large mulberry tree. However, because her soul was not fully developed, she could not move on to the next life. Instead, she roamed the earth and was required to collect 108 different human sorrows and desires in order to progress.