User blog comment:SethHeartphilia/Whos stronger Erza or Mirajane/@comment-24446496-20140425151258/@comment-112.198.204.222-20140916184306

Demon Sitri is just considered the strongest of her transformation because erza said so, but we can't say that it is her strongest demon take-over since Erza only took in account the mira years before Lisanna supposedly died, and not the present Mira today that acquired equal powers to the people that the second origin has been awakened, Mira's second origin wasn't said to have awakened she just trained for 3 months. If you take account the battle with one if Zeref's demon you can say that Sitri is her strongest because that is the final form she used, but Mira said that she holds back whenever she's with a family member ir a guildmate, and lisanna was there, so probably there was a much stronger transformation but she didn't use it because of lisanna