[W Gwyddel, Irish (-man)]. Irish owner of the magical cauldron in Culhwch ac Olwen; a steward of King Odgar fab Aedd. Diwrnach is sometimes described as a giant, and his cauldron will not cook the food of a coward. Olwen's father, Ysbaddaden Bencawr, demands that Diwrnach's cauldron be brought to Wales to provide food for his daughter's wedding feast. Arthur asks Odgar to persuade Diwrnach to give it up willingly, but the steward refuses. After another failed attempt to wheedle Diwrnach, Arthur seizes the cauldron and takes it to Wales brimming with Irish treasure. The cauldron also appears in the second branch of the Mabinogi and Preiddiau Annwfn [The Spoils of Annwfn].