DROS D'AVS
or Droes d'Aves

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.