Expain in Monsta language-

People from mainland go to island

Beat up people who lived there those who had darker skin (kinda a long standing action throughout history until heavy weight boxing was developed!)...but also while beating them up..some got down and did the 'boogie'.... thus slightly different appearance in Nippon features...in the end darker folk driven off....or as the case may be incorperatezatedmated.....in other words...

beat/boogie/gone/new.

hope that cleared it up for you...