Approaching Tintagel, Gawaine sees a party of knights crossing the heath, followed by a squire bringing a Spanish horse. Questioning the squire, Gawaine learns that he serves Droes d’Aves (with or without the accent marks, depending on the translation), who is going to take part in the tournament between Meliant of Liz and Tibaut of Tintagel.
Gawaine knows Dros well. So I suspect, did Chrétien’s target audience, from some contemporary literature apparently lost or terribly obscure to us today.
A connection with Druas of Druas’ Hill is probably not impossible, though it would seem to require a shift over the years from heroic to sinister figure.