A Red Cap or Redcap is a type of malevolent murderous fairy. They are said to inhabit ruined castles found along the border between England and Scotland. Redcaps are said to murder travelers who stray into their homes and dye their hats with their victims' blood. Redcaps must kill regularly, for if the blood staining their hats dries out, they die. Redcaps are very fast in spite of the heavy iron pikes they wield and the iron-shod boots they wear. Outrunning a redcap is supposedly impossible.
They are often depicted as sturdy old men or women with red eyes, taloned hands, and large teeth, wearing a red cap and bearing a pikestaff in the left hand. As time goes by they collect trophies, bits of armor from those they slaughtered. The eldest of the Redcaps are said to be like the ancient gods of war.
Powerful members of the Unseelie Court often use them as bodyguards and enforcers.