Ysbaddaden

thumb|So huge is his frame, Ysbaddaden requires great forks to prop up his eyelids. Illustration by John D. Batten (1892) "Ysbaddaden, Chief of Giants" (from roots meaning "hawthorn" or "infertile" - or perhaps implying both meanings), is the primary antagonist of the Welsh romance Culhwch and Olwen. A vicious giant residing in a nigh unreachable castle, he is the father of Olwen and uncle of Goreu fab Custennin.

Culhwch's father, King Cilydd son of Celyddon, loses his wife Goleuddydd after a difficult childbirth. When Cilydd remarries after brutally murdering his new wife's former husband, King Doged, the young Culhwch rejects his stepmother's attempt to pair him with his new stepsister. Offended, the new queen puts a curse on him so that he can marry no one besides the beautiful Olwen, daughter of the giant Ysbaddaden. Though he has never seen her, Culhwch becomes infatuated with her, but his father warns him that he will never find her without the aid of his famous cousin Arthur. The young man immediately sets off to seek his kinsman. He finds him at his court in Celliwig in Cornwall and asks for support and assistance.