How Did I Change from Strong to Weak?

In the early stage, I recorded the mental journey of the monsters and their growth in the process of becoming weak. Everyone has grown from weak to strong. The routine has been used*. There is a lack of understanding of people who have changed from strong to weak. As the saying goes, it is easy to go from poor to rich, but it is difficult to go from rich to poor. I want to show the psychological changes of the second type of people in the form of a novel. In order to make it easy to understand, I try not to incorporate the writing method of Western stream of consciousness. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.