A piru is a fiend or demon in Finnish mythology.
[1] However, piru lost its original meaning and refers to only demon in Finnish mythology.
[1] In folklore, a piru is often featured as a nasty spirit of the forest with which a smart aleck either wins or loses a battle of wits, giving or receiving a forfeit in return.
[citation needed] "Piru" is also a mild swearword in Finnish.
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