User blog comment:Arachne sama/Ch. 500 Jidanbou and Rin acting strange mystery/@comment-8669536-20130607215412

It most probably is a Quincy. It has been shown that certain Stern Ritter members wear customised uniforms, for an example Shaz Domino's uniform seems to be different from the standard Vandenreich uniform. And besides, who and what else could it be?

It's probably some unknown Stern Ritter with the ability to control people. Something like: Stern Ritter C, The control. Or something like that, but it can be safely assumed to be a Quincy since the event took place during the Vandenreich invasion and since it has been shown that certain Quincies possess unique abilities.

But this is just my theory.