User blog comment:FairyRaven/Fairy Tail Chapter 429 & 430: Code Blue & Purification Ritual, Review and Commentary/@comment-4449950-20150421055626/@comment-38.116.192.70-20150422135912

I think FRogue is blaming Gray for not being there. You can assume that Gray didn't help/didn't make it in time to save Frosch. This leads Rogue to blame Gray and turn to the Shadows.

But then again, I could be wrong.