User blog comment:Xilinoc/Ch. 597 - Winded by the Shadow/@comment-11446176-20140919004504/@comment-24384892-20140919021543

I agree it was too early and unexpected for Sternritter W to appear, but it's about time that one of the three unknown Sternritters finally revealed themselves. I've been waiting forever to find out who are the last three Sternritters that still haven't appeared.

With that said, there are now two more unknown Sternritters. I get the feeling that Ichigo and his friends will eventually confront one of them. For all we know, there might be a Sternritter waiting somewhere right now to attack Ichigo.