User blog comment:B214/Volume 21 info & spoilers/@comment-4547267-20160319075454/@comment-27168967-20160320175206

I'm not too sure that it's going to be very different from the EX we had been shown but at the very least there's going to be one extra kid for Issei if I'm not wrong. However, if the dragon transformation in EX is anything to go by, there might be another power up coming for Issei.