User blog comment:IamJakuhoRaikoben/Chapter 431 & 432: My sword is... & Brair in Love, Review./@comment-5894890-20150429033859/@comment-93.232.217.209-20150429115413

i guess aizen is simply strong because having a (just) intelligent villain in a shonen-manga would be incredibly boring. like:

I broke through all your traps, slayed your guards to rescue the princess, but your evil deeds are never to be forgiven. here i stay, stil covered in the blood of your enemys. No longer the weak boy that set out to this journey, but a man, who would gladly give his life to murder you! Now grab a sword and fight - yea, bout that, i cant fight, so you won.

having a villain who is stronger than anyone else (even with no further explanation) is okay. eg if you look at dragonball: how could a earth-scientist (whos planets strongest fighter is around a third of the strengh of the avegare space-soldier) build something a dozent time stronger than the strongest beeing in the universe? cell is a stu-character, no matter how you look at him. but its okay, because he is a villain. same with aizen.

anyway, erza is not a villain, so if she is a sue its bad.