well its the random humour thats used here like in lucky star or ichigo mashimaro or azumanga or..you get my point
its about this guy(the guy on the cover) hes an "alien" taking over other planets and of course his next target is earth..
when he arrives on earth planning on invading..he sees theres noone who is actually fighting back so he starts to create the earth terra rangers or something(they look exacly like the power rangers!) like that to protect the earth so that he can fight them and invade earth "properly"..get the irony?
apparently he was raised watching too many "earth" anime and tv shows
a joy to read i was literally laughing my head of!!
if this rewiew was not helpful i beg your forgiveness..im new..:P