The Magical Negro: o tropo (clichê) do personagem secundário negro que ajuda o protagonista branco

"The basic structure of this magical African American [...] character is as follows. He must have no history; he arrives from somewhere and returns, but those places remain vague and other worldly. He has a threatening aspect; he’s the Big Black Man and a drug dealer, a musician, a thief, a drifter[1]; there is initial danger, which makes the White people nervous in some way. He has magical powers, again rather vaguely defined but not the sort of thing one typically encounters; his sole purpose in the story is to selflessly use those powers to help a White man. He remains “invisible” in the text; the Black figure exists outside of any community of his own and is not recognized in any significant way by the White community that the main character belongs to." (http://www.ejumpcut.org/archive/jc45.2002/colombe/)

http://en.wikipedia.org/wiki/Magical_Negro