Night spirit

Supernatural beings in Slavic folklore come in several forms, and the same name can be spelled or transliterated differently according to language and transliteration system.

As is common in folklore, there is no standard set of characteristics, or names, and spirits or magical creatures are referred to by many names, often identifying their function or the place or environment of their activity. Such descriptive terms include:

The Vila are the Slavic versions of nymphs, who have power over wind, which they delight in causing storms of high winds. They live around hills, mountains, and high mounds. (cf. Leimakids, Limnades, Oceanids, Dryads, Nephele). They can appear as a ghost-like figure with a long billowing cloak wrapped around them.

In Polish mythology, the Wiła (pronounced [ˈviwa]), and in South-Slavic mythology the Vila (Serbian pronunciation: [ʋǐːla]), are believed to be female fairy-like spirits who live in the wilderness and sometimes in the clouds. They were believed to be the spirits of women who had been frivolous in their lifetimes and now floated between here and the afterlife. They usually appear as beautiful maidens, naked or dressed in sparkling beautiful white dresses, green skirts of leaves, and special fabulous blue robes.

It is said that if even one of their hairs is plucked, the Vila will die, or be forced to change back to her true shape. A human may gain the control of a vila by stealing a piece of the vila's skin. Once burned, though, she will disappear.

The voices of the Vilas are as beautiful as the rest of them, and can form large gusts of winds that can lift houses into the air. Despite their feminine charms, however, the Vila are fierce warriors. The earth is said to shake when they do battle. They have healing and prophetic powers and are sometimes willing to help human beings. At other times, they lure young men to dance with them, which according to their mood can be a very good or very bad thing for the man. They will kill any man who defies them or breaks his word. Vila rings of deep thick grass are left where they have danced; these should never be trodden upon, as this brings bad luck.

...
Wikipedia