User blog comment:Xilinoc/Ch. 611 - The Soul King Dies (edgy as ever, Kubo)/@comment-26815763-20141227013741/@comment-24963493-20141227022826

It's not just their Vollstandig, though. It was also the fact that their power levels increased due to Yhwach taking away all the other Stern Ritter's powers and using it to boost his Elites' powers.