Triomadac?
In Arthour and Merlin, a king who served King Rions (Ryons) and who opposed Arthur at the battle of Aneblayse.
His name is a corruption of “Roi Minadap” in the Vulgate Merlin.
See also
Minadap | The Legend of King Arthur
Source
Arthour and Merlin | Late 13th century
