User blog comment:ClassicFan92/Theory on Irene/@comment-212.119.235.218-20160912141116/@comment-29693708-20160912170439

how? erza's magic awakened in the tower of heaven and she used it to throw tools at the cultists (plus erza has never displayed the ability to use enchantment); If she made Irene you would think she would have appeared next erza to fight the cultists on her behalf.

Irene could want erza dead for a number of reasons that don't have any thing to do with fear, one possible example could be; given Irene's protectiveness of those she considers family (she referred to the sword girls as her children, implying such) she could be protecting family in alvarez (i.e. a husband and her biological kids), since betraying alvarez would put them in danger, so she intends to kill erza to ensure their safety, the needs of the many outweigh the needs of the few, style. but since she has qualms about killing erza herself, she sent Neinhart to do it.