User blog comment:B214/Volume 23 discussion blog/@comment-73.46.6.122-20170322143202/@comment-31137559-20170322155143

It could just be Rudiger watching it from where Rias and her team is at. It makes sense since he came up with the strategy in the first place and is smiling to himself. It's an image of Rudiger far away. I'm 99% sure that's Rudiger.