Okay... so, this may be a bit out of the blue, but when this happened:
The first thing I thought was: is Hitsugaya being hollowfied? The way the blackness is engulfing him - specifically, his iris in the bottom panel - reminds me of the way the sclera of someone being hollowfied turns black, just like it did when Ichigo hollowfied. Thinking about it, those who had their bankai stolen were able to overcome the quincy possession of their bankai by hollowfying temporarily, so who's to say that the shinigami can't regain control of their minds from the quincy as they did with their bankai by hollowfying? Then, I saw that Kensei and Rose were also zombies, and given that they were vizards, that seemed to render my theory redundant. The only thing I can suggest now, is that maybe it works differently, for zombies who were dead prior to being zombified (Kensei and Rose) and those who weren't (Hitsugaya, and for all we know, Matsumoto). Alternatively, this was just a representation of Hitsugaya's pain, which would be humorous, given all this speculation I've gone to the trouble of sharing.
Before I move on, about Hitsugaya's iris: at first, it's the dull colour it became when he fell under the control of Giselle. Then, it returns briefly to the blank way it used to be drawn in the manga, as does his skin tone, as if reverting from his zombified state. Is this supposed to represent something, or am I reading too deeply into things? Finally, of course, it all becomes engulfed by the blackness, which I have presumed to be some sort of hollowy-stuff.
There's not a lot else I had to say on this chapter, other than voicing my annoyances at Kubo's fodderisation of some characters, and over-powering others. In this instance, it was the three sternritter whom Byakuya slayed without any trouble. Given that Byakuya had trained in the Soul Palace, I suppose it's to be expected, as Rukia managed to defeat As Nodt and unlock bankai by doing the same thing. I'm still annoyed at the lack of good fights, and happy-go-lucky sternritter. *groans at thought of Pepe*