Before he can win Olwen's hand, Culhwch ap Cilydd must complete a number of seemingly impossible tasks given to him by Olwen's father, the giant Ysbaddaden. One of these tasks is to retrieve the comb and scissors from the head of the vicious boar, Twrch Trwyth. As it is impossible to hunt the boar without Gwyn's aid, he is called upon to join Arthur and his retinue against Twrch Trwyth. During the hunt, he is mounted on Du y Moroedd, the only horse that can carry him. Both Gwyn and Gwythyr set out with Arthur to retrieve the blood of Orddu, witch of the uplands of hell.
Before he can win Olwen's hand Culhwch ap Cilydd must complete a number of seemingly impossible tasks given to him by Olwen's father, the giant Ysbaddaden. One of these tasks is to retrieve the comb and scissors from the head of the vicious boar, Twrch Trwyth. As it is impossible to hunt the boar without Gwyn's aid, he is called upon to join Arthur and his retinue against Twr,ch Trwyth. During the hunt, he is mounted on Du y Moroedd, the only horse that can carry him. Both Gwyn and Gwythyr set out with Arthur to retrieve the blood of Orddu, witch of the uplands of hell.