is a prince of the empire of Melniboné
, cousin to Elric
and the brother of Cymoril
In possession of Mournblade Yyrkoon attempted to usurp the Ruby Throne from his cousin twice, seeing Elric as unfit to rule as Emperor due to his perceived disrespect for the traditions of Melniboné.
Yyrkoon imprisoned for treason
Yyrkoon's demonic form in the Fifteen Planes of Corum's World
Yyrkoon wielding Mournblade in battle against Elric