There were various people named Comaetho in Greek mythology.
One of them was the daughter of Pterelaos, king of the Taphians. She fell in love with Amphitryon, the leader of the Theban army, with whom the Taphians were at war. Thebes was on the losing side, but Comaetho, wanting to help Amphitryon, cut her father's hair, which were the source of his invincibility and immortality. After the victory of Thebes, Amphitryon had Comaetho killed because of her treason to her own people.
Another Comaetho was the priestess of Artemis at a temple in the region of Patrae, who had fallen in love with Melanippus. It was forbidden to marry each other, so they had sex in the temple; Artemis was infuriated and sent famine in the region. When the people found out the reason, they sacrificed the two lovers to appease the goddess. Since then, a young couple should be sacrificed each year until a king would introduce a new god to the city. This king was Eurypylus, who spread the religion of Dionysus.