Constantius also know as ''the falcon'' is the secondary antagonist of the Conan story ''A Witch Shall Be Born''. Constantius was the Kothian leader of a bloodthirsty army of mercenaries and he was chosen by the witch Salome as her right-hand man for his utter lack of characteristics men call good.

After Salome frees Constantius from the dungeons, the two quickly replace Taramis, the real queen of Shem, with Constantius torturing the queen for his amusement. Salome's only response is to gleefully tell Constantius to "tame her as he will." Under the ruling hand of the duo, Taramis's kingdom becomes depraved and dissolute. Constantius's soldiers abuse and violate the people at will with any who resist facing death or slavery. When only Conan realizes that "Taramis" is an imposter, Constantius captures him and crucifies him in the desert, leaving him in agony and to be devoured by the vultures while still alive, but Conan manages to escape.

Map of the Hyborian age :