@Book Sounds like one of the ancient ways of naming bad things, like the floating castle of ebony towers called "The Black Omen", or the spellsword of darkness being referred as "The Black Emperor", meanwhile beings of good get names like "The white priestess" or "the white fortress", they just didn't think that much while naming mages in this world, so "The Black King" it is... magic color+king rank... funny enough, if you mix the primary colors you get white, not black.
"Being hero or a villain just depends on the things you choose to destroy to keep on living, still, you should live strong with an unwavering heart" -Dewani90-