User blog comment:R. Lawton/How strong are some the GMG characters in comparison to Fairy Tail/@comment-5894890-20130911002816

Erza didn't activate her second origin until her final battle with Minerva. And Erza was still able to match up with her (except with Kagura hit her a few times before this --->), and landing a heavy blow on her (using nakama powers...). So technically Erza would be stronger than Kagura since she's twenty... something. In other words Erza at age 19(maybe 20?.. because they never tell her birthday) was fighting kagura who is near/is in her mid 20's without her second origin activated yet. As for the other stuff... You're going just have to read the comments below :P.