Hera was the evil queen of the Greek gods, whose main goal in existence became the destruction of Hercules. She finally came close to success after absorbing Zeus' power, but Hercules banished her to the abyss of Tartarus, the same void where the Titan Cronus was imprisoned.
Hera was later freed by Evander, son of Ares and Nemesis, at Zeus' urging. Her time in Tartarus removed her memory, and Zeus almost managed to make up for the wrongs he'd done- until Ares restored Hera's original memory. Still, Hera was touched by Evan's kindness, and when the boy was hurt as she battled Hercules, she felt remorse, leading to a reconciliation with her husband and stepson.
Hera later opposed Zeus in his bid to kill Xena's unborn daughter (who was prophecied to bring about the end of the Greek gods). As a result, Zeus destroyed Hera.
In the non-canon animated film Hercules and Xena: The Battle for Mount Olympus, Hera used the power of the Chronos Stone to awaken the Titans and use them against her fellow (now de-powered) gods. She was defeated thanks to Xena and Hercules.