The Hecatonchires were children of Gaia and Uranus. They were told to be even more ferocious, stronger, and willful than the massive Cyclopes themselves. Each of the three Hecatonchires were known to have 100 arms and 50 heads! The word Hecatonchire means 100 handed in greek.
The names of these beastly creatures were Cottus, Gyges, Briareus. Uranus, the lord of the universe, was disgusted by his demented sons, so, in a fit of rage, he threw them into Tertarus, the deepest, darkest pit on Earth. Gaia was anguished about the fact that Uranus had thrown her sons into Tartarus, so she asked the Titans to help retrieve them. Only Cronus, the youngest of the Titans, agreed to help.
The young Titan, Cronus, waited for Uranus under his bed. That night, when Uranus laid on it with Gaia, Cronus jumped from his hiding spot and decapitated his father. He threw the disembodied part over his shoulder, and it landed in the sea. This threw droplets of blood on the land, and it made the sea foam. The giants and nymphs were born from the drops of blood, and Aphrodite, goddess of love and beauty, sprang from the sea foam.
Exactly how Cronus helped free the Hecatonchires is uncertain because the sources vary. Some say Cronus was not even the person who helped the Hecatonchires, but Zeus was. It was said that, when Zeus freed them from Tartarus, the Hecatochires joined his rebellion against the Titans. The Titans were overcome by the barrage of stones being thrown from the monsters 100 hands, and they gave in to the Olympians.
The three ferocious Hecatonchires were famed in Greek mythology because of their 100 arms and 50 heads. They played a big role in the overthrowing of the Titans.