Drwc
Priest of the Holy Empire. He was the one who resurrected Arawn, using Riannon as a sacrifice, wanting Arawn to make him the next ruler of the new age. He was later killed by Arawn instead.
Near the end of the series he returns, resurrected by dark power and fights Arthur and Riannon once again. After losing against them he transforms into a monster as a final resort, but he is destroyed permanently at the hands of Arthur.