Glaistig

Sources preserve multiple, regionally varying origin strands. In some tellings the glaistig is an otherworldly fuath/faery-type being—an otherworld female associated with water, pasture and hidden folk. In other local narratives she is a mortal woman transformed or cursed (the 'Green Lady' house-ghost motif), sometimes murdered while wearing green, who continues to tend a house or estate. These strands coexist in the tradition and account for the glaistig's household, pastoral and wild aspects.

Accounts vary. She may appear as a beautiful woman (often described in some sources as grey-skinned with long yellow hair) or as a hybrid half-woman/half-goat resembling a faun or satyr; when goat-legged her lower half is commonly said to be concealed by a long green robe or dress. As a domestic 'Green Lady' she is reported walking castle corridors and performing household tasks. Some regional variants present wholly bestial goat or goat-like forms or water-spirit aspects.

Folklore attributes ambivalent powers and behaviours: she may act as a tutelary spirit protecting cattle, herders and deer and watching over children or household tasks; she may bestow favors or prosperity in specific clan tales. Conversely, she appears in stories that have her lure men by song or dance to drain their blood, mislead travellers by casting stones in their path, throw servants into disorder when offended, or punish cruelty. Her behaviour in most tales depends on treatment: offerings and respect secure protection, while insult or injury revokes favor and invites harm.