Gruddlwyn, Gwdolwyn Gorr
An Arthurian warrior who fathered the lady Eurolwyn.
As one of his tasks, Culhwch had to obtain a magical bottle from Gwydolwyn, which would keep warm any liquid poured into it.
Culhwch had to use the bottle to carry the blood of the Black Hag.
Source
Culhwch and Olwen | Late 11th century