Dark Knights are the villainous counterpart to the high-ranking Military officials that fought in the Middle ages (especially in the Arturian era), though, in fiction, they can come from any sort of era or even alternate world as long as they still carry the aesthetic and fighting techniques of the medieval knight.

Being a knight can greatly help a villain's magnificence as, even at their most morally bankrupt, knights are seen as icons of bravery, honor or at least elegance and style even in battle.