User blog comment:FairyRaven/Fairy Tail Chapters 338, 339, 340: Review and Commentary/@comment-5598380-20130706211549/@comment-1359322-20130707043654

Actually i think you're misunderstanding something, Mashima wrote the "Gates of Hades/Underworld/Netherworld" which refers to Tartaros not the type of Underworld you think.