Dark Knights (not to be confused with Batman) are Stock Characters of sorts in fiction, especially fantasies.

As their name implies they are often evil or misguided Knights, high-ranking Military people from medieval times or fictional equivalents. They can also be found in the modern ages but as a title rather than a position and Modern Knights share their medieval counterparts' traditional titles of "Sir" or even "Ma'am".

In some cases Dark Knights can be Arthurian or connected to Imperialists due to stories of King Arthur being set in medieval times or imperialism revolving around an oft-warped form of modern knighthood.