User blog comment:FairyRaven/Fairy Tail Chapter 346: Retrogression Magic, Review and Commentary/@comment-7418318-20130802133028/@comment-7418318-20130807152458

Well... so far we don't know whether he will get the 2nd half of the kyuubi too and whether he'll be able to controll it.

After all it's the evil (even more evil?) side that Minato sealed within himself if I remember correctly....

Incidentially this might also double as a way to tone him back down a bit, if he's unable to controll the reunited full Kyuubi and thus could only use part of it's power without the risk of being overwhelmed by it's hatred again, like it used to be.