Appears In: Young Hercules: Cheiron's Warriors
Kostas, an 'old comrade' of Cheiron's and an active soldier from Crete, is called in to be the substitute headmaster at the Academy whilst Cheiron is away at a wedding. An old-fashioned, crotchety older man, he believes in training beyond the point of exhaustion and feels that the Academy is no place for half-gods, former thieves, girls, or royalty.
When Iolaus comes up with the idea to disguise Hercules as an ogre to gain passage on a boat to Syracuse, they borrow the grouchy soldier's name. After that, Kostas makes no further appearance until the last chapter. He approaches Hercules, telling the half-god that he's going to recommend that Cheiron have them all expelled for leaving the Academy grounds when they were told not to. He also says, though, that he is ultimately going to leave such a decision to Cheiron himself and that, because Cheiron not only saved his own life but the lives of his wife and child as well during the war against Sparta, he's actually quite grateful to have been disobeyed.