Board Thread:General Discussion/@comment-24074672-20131120051033/@comment-8986886-20131128120308

YoAlex96 wrote: I also thought about the letter relating to their powers but you have to remember that it was Royd or Loyd (I don't remember) the one who defeated Kenpachi not Yhwach.

I see what you mean, however Kenpachi defeated Royd's twin brother Loyd with relative ease, along with two other Stern Ritter, before encountering Royd posing as Yhwach. My guess is that the difference in strength between Royd and Loyd at the time, was due to Yhwach having granted Royd additional powers, which he would need in his predestined fight with Yamamoto.

This is mere speculation, but Yhwach has demonstrated an ability to infuse Quincy powers into both Arrancar like Luders Friegen and Asguiaro Ebern, as well as into Quincy like Uryu; remember the ritual right after Yhwach named Uryu his successor? Yhwach is also able to extract the same powers, like when he used Auswählen.

My point is that the reason Royd was able to defeat Kenpachi, could have been due to a temporary power-up, much like what Ichigo experienced when he used his Saigo no Getsuga Tensho.