User blog:Bluefox87/Which is the first name monkey or luffy

Basically I brought this up from talking to this guy that sais monkey was luffy first name. I don't thin that's true because 1 all of luffy's family has monkey in it to it has to be his last name and second I know some Japanese say their last name first and their first name. but can someone tell me the which his is first name just so I can be sure?