The planet Fargaia is slowly but surely losing its greenery and becoming a wasteland. The severe environment and cruel monster threats are violent, but people still carry on living there. Such a withered world, but there are those who seek danger and adventure within the wilderness. People call them "Migratory Birds".

-- from: Wild Arms Advanced 3rd
Second Japanese Guide Book

"Migratory Birds" is the Japanese term which was translated as "Drifter" for the English version