DARKSTAR

Besides... The Good Guys wear Black

The color Black with it's positive side...

In Japanese culture, kuro (black) is a symbol of nobility, age, and experience, as opposed to shiro (white), which symbolizes serfdom, youth, and naiveté. Thus the black belt is a mark of achievement and seniority in many martial arts. These ranks are called dan.

Black Watch is the senior Highland Regiment of the British Army

Black tuxedos are worn at formal occasions known as black tie functions.
Many performers of European classical music or other serious art music dress in black for a concert or recital.
Lawyers and judges often wear black robes.

black cats hold them to be bad luck in the U.S. and good luck in the UK.

character of J.K Rowling