User blog comment:Xilinoc/Ch. 579 - THE UNDEAD 6/@comment-4207271-20140508062208/@comment-24913480-20140508081214

Giselle being the "Zone" doesn't seem likely. Quilge Opie, the quincy Ichigo fought on Hueco Mundo, was the "Jail" and he could create reishi prisons to trap his opponents (although it didn't work on other quincies). I doubt there's another sternritter with similar powers.