A trio of Arthur’s knights – Morfran, Sanddef (Sandde Bryd Angel), and Glewlwyd – who worked their will through their appearances: Morfran through his hideousness; Sanddef through his angelic beauty; and Glewlwyd through his enormous size, strength, and ferocity.
Morfran and Sanddef were said to have survived the battle of Camlann because of their countenances.
Source
Triads of the Island of Britain (Welsh ”Triads”) | 11th century to 14th century