One who practices 'Black Magic'. i.e. is capable of seducing European women, often by the use of ancient magic potions such as Rohypnol.
N1: I see that nigger has bagged himself another whitey, know what I'm sayin'?
N2: Like yo. Dat nigger is one sweeeet Negromancer, he's gonna romance her good.
N1: Although technically it's considered rape.
N2: Quite so.