User blog comment:SoulReaperBleach1/IZURU KIRA T.T/@comment-2211792-20130729042030/@comment-10205398-20130730173038

Personally, I think Kubo is deliberately using vague/sketchy wording in regards to Izuru's fate because he plans on revealing that Izuru is in fact still alive. Characters' reiatsu have "disappeared" several times in the series, but they've ended up being alive. A "fallen" soldier doesn't have to be dead, just incapacitated. Plus, Shuuhei doesn't seem that shook up about it, and the two have been known to be close.