*Phew* now that I'm calm. I think the Zero Squad is the Soul King's army, and that this arc pretty much links into the other arcs in which Aizen just wanted to kill the Soul King. This chapter was better than the last one, that chapter was just awful. The explosion could be Ichigo and Urahara, or Yoruichi, or the resistance in Hueco Mundo or the Visored - though I highly doubt they'd show up. Maybe its Uryuu? Haha.
I really hope Soi Fon is one of the war potentials - with Hitsuguya, because those two are just so bad-ass.