Hafgan

Hafgan is one of the kings of the otherworld, Annwn, in Welsh mythology. He appears in the First Branch of the Mabinogi as the main rival of Arawn, the other king of Annwn. The dominions of the two kings sit side by side, and Hafgan is constantly warring against Arawn. In the story Pwyll, Prince of Dyfed, Pwyll, in order to gain Arawn's friendship, agrees to switch places with him for one year and one day and to battle against Hafgan in order to rid Arawn of his difficulty. Before they exchange places, Arawn gives specific instructions to Pwyll to kill him with one stroke and no more. In the past when Arawn had battled and had struck Hafgan nearly to his death, Hafgan had begged him to give another stroke, and when Arawn had done so, Hafgan recovered from his injuries and was in good health for battle again the next day."