Arawn is the ruler of Annwn in the First Branch of the Mabinogi, a central work of medieval Welsh prose. Annwn is an otherworldly domain of wealth, feasting, and supernatural power. It is not simply the Christian hell, and Arawn is not portrayed as a Welsh equivalent of the devil.
A year and a day with Pwyll
Pwyll encounters Arawn after driving his hounds from a stag taken by Arawn’s pack. To make amends, Pwyll agrees to exchange appearances and rule Annwn for a year and a day. He defeats Arawn’s rival Hafgan exactly as instructed and honors Arawn by refusing intimacy with his queen.
Kingship and reciprocity
The episode establishes friendship between Arawn and Pwyll through restraint, loyalty, and fulfilled obligations. Arawn later sends otherworldly pigs to Pwyll’s son Pryderi. His role is therefore that of a sovereign and ally, not merely a frightening lord of the dead.
Limits of the surviving record
Arawn appears most fully in the Mabinogi. Later summaries sometimes combine him with Gwyn ap Nudd, the Wild Hunt, or broad ideas about an underworld god. Those associations belong to different texts and later interpretation, so they should not be treated as one consistent ancient biography.