Thread:FairySina/@comment-7893396-20141108172854/@comment-25994611-20150124203025

A part of the plot is that the main four aren't from Japan, but from a different sort of world, like Major Land or Blue Sky Kingdom. They go to Japan for the mission they were given and while staying there, they try to keep a low profile and not blow their cover, being from another world.

So they get a place to stay, enroll in school and takes on new identity's that makes them fit in better. Therefore also taking on casual japanese names, to blend in as much as possible, until their mission is fulfilled.