The Information below details information on Megara from Greek Mythology, which differs alot from the character of Megara from the disney film "Hercules":
In Greek mythology, Megara ("great houses")was the oldest daughter of Creon, king of Thebes. In reward for Heracles' defending Thebes from Orchomenus in single-handed battle, Creon offered his daughter Megara to Heracles and he brought her home to the house of Amphitryon. She bore him a son and a daughter, whom Heracles killed when Hera struck him with temporary madness; in their hero-tombs in Thebes they were venerated as the Chalkoarai. In some sources Heracles slew Megara too, in others, she was given to Iolaus when Heracles left Thebes forever.
In some traditions, in order to atone his guilt, he was forced to perform the Twelve Labours, but in Euripedes' tragedy, Heracles' return from his encounter with Cerberus in Hades begins the agon.