User blog comment:IamJakuhoRaikoben/Chapter 484: The Monstrous Six, Review./@comment-70.179.149.246-20160510122715

We've seem pretty odd battle pairings in this arc, prime example would be Sky sisters vs. Dimaria and Erza vs. Ajeel. I have this feeling that Mashima is going to pair up Mirajane with a different Spriggan and not Irene. Irene will probably be reserved as the main boss at the north and they would need back up to defeat her. Likely Oracion Seis, and I'm predicting a Racer and Mirajane team up due to their history on the Key Starry arc, despite it not being in manga. If not, that will buy them enough time until some more fairy tail members arrive for back up, likely Erza (since she really has to meet Eileen, plus a Minerva+Erza+Mirajane+Kagura vs Eileen battle would be epic), Kagura (well, wherever Erza is, Kagura is there), and some other character that would be relevant to this new Spriggan Rahkeid. I believe he has not been introduced due to connection to another fairy tail member.