Efnysien

In Welsh mythology, Efnysien or Efnisien was the son of Penarddun and Euroswydd. His twin was Nisien.

His half-sister, Branwen, was courted by the Irish king Matholwch, who gave her brother, Brân, horses to curry favor. Efnysien mutilated the horses; Matholwch was irate until Bran gave him a cauldron which restored the dead to life.

Branwen, was treated cruelly by her husband, Matholwch, in Ireland. Bran sailed from Wales to Ireland to rescue her with his brother, Manawydan. When Matholwch saw the giant, he asked for peace and built a house big enough for him. Matholwch agreed to let Bran live with them and give the kingdom to Gwern, his son by Branwen. The Irish lords didn't like the idea, so they hid themselves in flour bags to attack the Welsh. Efnysien guessed what was happening and dispatched them one by one, fumbling around the flour sacks until he found each warrior's head and strangled them. Later that same evening, at a feast, he finally sparked a war between the Irish lords and the Welshmen when, in an act of betrayal, he threw his nephew Gwern headfirst into a fire.

In the ensuing battle, Efnysien sacrificed himself to save his compatriots by leaping into the magical cauldron used to revive the fallen Irish warriors and shattering it. Bran was mortally wounded and instructed his men to cut off his head (which survived the ordeal by some feat of magic) and take it back to Wales. Branwen went to Aber Alaw and died there. Bran's head, still alive, was buried in London. Legend said that as long as the head was there, Wales (the land of the Mighty) would live on.