User blog comment:FairyRaven/Fairy Tail Chapter 471: Until the Battle is Done, Review and Commentary/@comment-74.43.16.57-20160201155641/@comment-1776824-20160201160445

God Serena wasn't plucked off to show how powerful Acnologia was. God Serena was plucked off because Hiro designed him to be one of the most powerful members of the Spriggan 12, and after the 2-5 Wizard Saints were completely wiped and nearly killed by him only using half his power, the only feasible way to have him taken out was to have someone who was confirmed to be stronger deal the killing blow. This person just happened to be Acnologia, and as such, Hiro made God Serena a Dragon Slayer to justify this. It's way better than Gildarts coming out of nowhere and flooring God Serena, honestly.