In some old Welsh texts, Eliwlod is a nephew of King Arthur. His father is Madoc, son of Uther Pendragon, an obscure brother of Arthur's mentioned a very few times in Welsh literature. Eliwlod appears in the Welsh Triads, where he is called one of the three "Golden-Tongued Knights of Britain," alongside Gwalchmei ap Gwyar (Gawain) and Drudwas ap Tryffin. He pays a postmortem visit to his uncle in the form of a raptor in the poem Arthur and the Eagle.
References
Eliwlod Wikipedia(Text) CC BY-SA