To say I am not dark in Spanish, you would say:
I ser no oscuro
oscuro
piel oscura
luna oscura
Translation: morado oscuro
Cerveza negra or cerveza oscura.
Moreno or morena.
"Tiene pelo negro" means he/she/it has black hair. "Pelo oscuro" means "dark hair."
Either "Señor Tenebroso" or "Señor Oscuro".
El caballero oscuro
dark = oscuro
(De) cabello negro y flacucho (flacuchos / flacucha / flacuchas) --- offensive
It depends what you mean by dark skinned, but there are darker skinned spanish people.