Owner of the magical birds Adar Llwch Gwin. The birds were a gift from Drudwas's wife, a fairy woman; they could understand human speech and fulfilled all their owner's commands. In a contest with Arthur, Drudwas gave orders to the birds to kill the first fighter to reach the battlefield; when Arthur was delayed Drudwas was torn to pieces by his own birds.
See Rachel Bromwich, Trioedd Ynys Prydain, rev. edn. (Cardiff, 1978), 327ff., 549.