Arawn is the King of Annwn. He appears in Welsh sources, including the Mabinogion and the Welsh Triads. According to Triad 70, he, Urien, and Lleu are triplets. Their father is Cynfarch and their mother is Nefyn daughter of Brychan Brycheiniog.
His interactions with Pryderi have been compared to Gawain’s interactions with Bertilak in Sir Gawain and the Green Knight.
His role as King of the Otherworld was later attributed to the psychopomp Gwynn ap Nudd, brother of Edern ap Nudd.