Hmm, might be a stupid question, but does Magus really has a name in 600 A.D.?
Yeah, you know in CT DS, those villagers in Medina call him fiendlord, which is supposed to be his title. But in JPN version, everyone calls him 'fiendlord', which means they don't use or don't know his name at all, unlike in ENG versin, he has a name as Magus plus his title.
His JPN "name" 魔王 doesn't sound like a name at all, I mean, something like "his majesty", "the boss", etc...
So maybe that's why in ENG version, they give him a serious name?