User blog comment:FairyRaven/Fairy Tail Chapter 371: Tartarus Arc, Part 2: Song Of The Heavenly Dragon, Review and Commentary/@comment-4489126-20140214145808/@comment-7418318-20140214150041

It's most likely a title for the entire part, just like "Prologue" and "Sinners and Immortals" (or whatever it was) were.