Arawn

Arawn was the Lord of Annwfn (Otherworld) in the First Branch of the Mabinogi – Pwyll Lord of Dyved (Mabinogion). Arawn befriended Pwyll when they encountered one another in the woods. Arawn offered Pwyll to take his place as Lord of Annwfn for one year and a day. Pwyll would be transformed to look like Arawn so that Pwyll could fight Havgtan (Hafgan) in his place. Havgtan was also a Lord of Annwfn and Arawn's archenemy. Havgtan could only be killed in one blow, for the second blow would magically heal Havgtan. So Pwyll mortally wounded Havgtan and refused to strike another blow, so Arawn's enemy died.

Arawn had a beautiful wife who was unnamed. While Pwyll was pretending to be her lord and husband, Pwyll did not take advantage of it, making love to Arawn's wife. Arawn was so surprised that Pwyll would protect his wife's chastity that they became friends and allies. Arawn richly rewarded Pwyll for both deeds. It is believed that Arawn sent Rhiannon to become Pwyll's wife.

Arawn also gave pigs to Pryderi, Pwyll's son, when Pryderi became Lord of Dyved. These pigs were stolen by Gwydyon (Gwydion) in the Fourth Branch of the Mabinogi – Math Son of Mathonwy. This led to a war between Dyved and Gwynedd, where Pryderi was killed in single combat against Gwydyon, the nephew of King Math of Gwynedd.

Arawn was also said to possess the magic cauldron, which Arthur tried to steal in the obscure poem in the Book of Taliesin called Spoils of Annwfn (Preiddiau Annwfn).