Shadow6865@AOL.COM wrote:

                        The most important question that is left unanswered
is "Where is the United States military?"  The US is still required to prtect
Japan from Invasion and despite popular belief they are still one of the most
effective and powerful military powers in the world. Unless our secret
invaders are from the US (which I doubt) you just leave too much out of this
fanfic

There are only two real options.  They have to be from the States, or 
they have to be the Japanese military.  (Well...strictly speaking they 
could be extradimensional)