This book basically makes the first 4 books in this series meaningless. I goes from being about progressing through the ranks to being about world building. I have nothing against world building books, but that is not what I signed up for in this series.
The book was also just filled with fluff. He just jumped around through a series of low intensity tasks. The main enemy was a crab . . . that he one hit killed after ranking up.
The first 4 books were great, but this series probably should have ended there. There is currently 12 books in the series. Is it worth continuing.