Dark is Evil
Dark, black, or simply dimmer things are depicted as evil or evil things are consistently clothed/colored dark and anything that becomes evil gains darker coloration.
Alternate name: Black is Evil
The first video game about Dark is Evil was released on March 28, 2002.
Milder instances are where evil things explicitly prefer darkness, making it their domain and associating it with being evil (no good character/being would prefer darkness in similar manner in the setting).
See also: Evil by default