Gaia was really angry that Zeus had punished some of her children really hard after the victory against the titans, so she gave birth to some really ugly creatures. They had snakes instead of hairs and their bodies ended in a dragon tail: the Giants. The first work these creatures had was to head to the Olympus, the house of the gods, to destroy everything.

Though even if the giants were descendants of the gods, they were not immortal. However, the Moiré had already foretold that for their victory the gods would need the help of a mortal. Gaia planted a herb that should make the giants immortal, but fortunately Zeus discovered it before they could use it and he destroyed the herb.

The mortal help came in the form of Heracles, who supported the gods in their fight against the giants. This was somehow the last hard exam for the gods, who managed to stand a second hard battle about the ruler ship of the earth even after the battle with the titans.