A special duel among members of the Invictus. The duel can be called for any reason, but if it is a foolish or stupid reason it can be safely ignored. Usually done between equals to gain rank or in vengeance for a grievous insult. Not accepting can be seen as submission to the other, a form of permanent submission. If challenged one may appoint a champion to fight in their stead. During Monomancy no help from the outside is allowed by punishment of death.