In Celtic mythology, werewolves are primarily found in Irish and Scottish folklore, where they differ significantly from the modern "monster" figures. Known in Ireland as the Faoladh or Conriocht, these beings were often considered guardian spirits or protectors of the community, though some traditions also spoke of fearsome mercenary warriors who transformed into wolves for battle.

Irish Folklore: The Faoladh and Ossory
The most famous legends originate from the medieval kingdom of Ossory (modern-day County Kilkenny and County Laois).
- The Werewolves of Ossory: Described in the 12th-century work Topographia Hibernica by Gerald of Wales, these were people cursed by a saint (often St. Natalis or St. Patrick).
- Every seven years, a man and a woman were forced to leave their human forms and live in the forest as wolves.
- Unlike typical werewolves, they retained their human reason and were even known to speak.
- The Guardian Spirit: In many tales, the Faoladh were benign. They were said to protect children, help the wounded, and guide lost travellers safely out of the woods.
- Laignech Fáelad: This legendary figure was the ancestor of the kings of Ossory and was the first to "go wolfing" (transform into a wolf). His lineage was said to possess the power of shapeshifting.
- The Wolf-Warriors: Some lore describes the luchthonn ("wolf-skins"), mercenary warriors who were followers of the god Crom Cruach. They were feared for their brutality in battle and were said to fight for any king willing to pay them.
Scottish Folklore: The Wulver
In Scotland, particularly in the Shetland Islands, the equivalent creature is the Wulver.
- Appearance: It was described as having the body of a man covered in short brown hair and the head of a wolf.
- Character: The Wulver was considered a distinct species rather than a cursed human and was famously kind-hearted.
- Behaviour: It was known for its patience while fishing from "Wulver's Stanes" (Wolf Stones) and for leaving fresh fish on the windowsills of poor or hungry families.
Key Characteristics in Celtic Tradition
- Transformation: In some Irish versions, the transformation occurred by the person's soul leaving their physical body to inhabit a wolf form, while the body remained in a trance-like state.
- Repercussion: Any injury sustained by the wolf would appear on the human body once they returned to their original form.
- Goddesses and Shapeshifting: The war goddess The Morrígan was also known to take the form of a red wolf during combat.