User blog comment:Omega natsu2/Chapter 364: Tartarus Arc, Part 1: Immorality and Sinners, Predictions./@comment-5303512-20131211235214/@comment-8153438-20131212014942

The prologue has 8 chapters, Part 1 may have 7-8, and we don't know how many parts until the arc ends.. Maybe each part will have an average of 8 chapters each..