User blog comment:Omega natsu2/Chapter 387: Tartarus Arc, Part 4: Father and Son, Predictions./@comment-110.20.169.85-20140530232519/@comment-4999650-20140530233919

No, the translators or the publishers messed up~ It's Part 4. Part 3 was Prince of the Underworld, Part 2 was the Song of the Sky Dragon and Part 1 was Immorality and Sinners.