User blog comment:IamJakuhoRaikoben/Chapter 470: The Hybrid Theory, Review./@comment-5268982-20160126122255/@comment-27281341-20160127134652

Not any kind of victory will look like an asspull against Acnologia. If Natsu defeat's Acno 1v1, then yes, it will be BS. If just a combo of 7DS, 1 of them a kid. the other 1 useless and 2 weak compared to the stronger ones beat him, well it might be BS, but not so much. But,if Natsu becomes a dragon, Acno gets an Etherion shot to his face, Zeref helps Natsu, Sting, Rogue, Gajeel and Wendy use Dragon Force & Laxus and Cobra give them a hand & 1 or 2 of them die then it won't be BS. It will be epic.

God Serena was nevr meant to be a major character to begin with. He was just there to show us that the Spriggan 12 are way above the WS, give us a glimpse of Acno's powerin his human form AND give a hint about Acno's purpose/motive without killing an already known character. Imagine what would happen if instead of GS, Acno one-shotted Cobra. Now that would be a waste of character, wouldn't showcase Acno's power nor give us a glimpse about how strong the S12 are compared to the 10WS. Hiro managed to do all 3 just by killing one character. The other stuff, like traitor, former WS were just there to give GS a 2 dimensional personality.