User blog comment:Xilinoc/Ch. 538 Standing On the Edge/@comment-2243814-20130522230210/@comment-4243147-20130523040158

I don't think that is Hollow Ichigo. Hollow Ichigo and Tensa Zangetsu merged. Shiningami spent time with the Asauchi pouring their reiatsu into them thus forming their Zanpakuto. That is most likely the spirit form of Zangetsu.