User blog comment:Xilinoc/Ch. 607 - THE MASTER/@comment-24384892-20141127211606/@comment-5693502-20141127232757

I've been wondering that for a while as well. While the Elite Sterns are dealing with the Royal Guard and Yhwach is battling Oshō, maybe those two are setting something up from behind ? Or maybe even going to the Soul King's quarters to do... something...??

I think Oshō's shikai has something to do with crossing things out (in both a figurative and literal sense) and anything he crosses out has its power nullified. That black stuff coming from the tip of his blade looked like ink (but a part in my head also thinks it might have been space that was slashed).