Piru (spirit)
A piru is a fiend or demon in Finnish mythology. In folklore, a piru is often featured as a nasty spirit of the forest with which a either wins or loses a battle of wits, giving or receiving a in return. In many cases, poltergeist and haunting phenomena are described as "pirus". The Devil may be referred to as Piru, or Pääpiru, the main piru.
"Piru" is also a mild swearword in Finnish.
