User blog comment:CNBA3/Chapter 413 Review/@comment-203.111.234.105-20141222171629/@comment-7418318-20141223001357

While I too would like to know more about their pasts, I don't think their rivalry needs any explanation.

On one side we have "Demon Mirajane" a very agressive woman with a need to be the strongest, who doesn't let anyone tell her what to do.

On the other side we have Erza, who always tries to tell everyone what to do and never backs down from a threat.

Isn't it just natural that two such women would sooner or later clash with each other and become rivals?