Black

"The Brunet Assassin" Black is a notorious assassin and criminal. He was imprisoned in the Underworld until being freed by Miranjo.

Appearance
Black is a tall man with dark blue eyes, long black hair, thick eyebrows, a beaky nose, and a pointed chin. He wears a black tunic over black leggings. He wields an exceptionally large, two-handed sword.

Personality
Like the other criminals freed from the Underworld, Kingbo has a vicious and savage disposition, and doesn't think twice before attempting to murder his benefactors.

Black in particular seems to be very nasty and opportunistic, openly laughing when Kingbo assaults Daida, and disparaging the Bosse Kingdom at every opportunity.

Plot
Black is one of the Underworld prisoners freed by Miranjo to conquer the Bosse Kingdom.

It's implied that he has an existing relationship with Red, due to their similar names and aliases. The two also worked in unison to attack Apis and Miranjo when freed from the Underworld.

Trivia
Black's nickname, "The Brunet Assassin" is not a typo. It's the masculine form of the more common word brunette, meaning a person with dark-brown hair (though it is sometimes used to describe black hair as well).