Dark Celtic history - Ly Erg and the Redcaps

Ye Olde Scot - the Celtic culture channel.
Dark Celtic history - On the Scottish borders are two evil types of fairies who are linked by a curse and doomed to haunt battlefields and ruined castles. One is born from the other to become something greater, and therefore command the lesser of the two. The first is a Red Cap, and it looks like a malevolent murderous dwarf or goblin but is really a fairy found in the Folklore of the Scottish borders. They are said to inhabit ruined castles found along the border between England and Scotland. In the past with wars and battles ever-looming, they had plenty of unattached people they could kill, These days unattached people are hard to come by, Redcaps were forced, in order to survive, to murder travelers who stray into their ruined castles. Their curse causes them to dye their hats with their victims' blood, Redcaps must kill regularly, for if the blood staining their hats dries out, they die. With killings rare, Redcaps will keep their victims hidden on the brink of death, as a source of blood for their hats. Redcaps are very fast in spite of the heavy iron pikes they wield, and outrunning a redcap is supposedly impossible.