The cause of the First Giant War was the gods' defeat of the Titans. In anger, Gaea took Tartarus, the protogenos of the abyss, as a husband and bore the race of giants, each giant being the rival of a different Olympian god or goddess. Like the Olympians, the giants were led by the youngest of their number, Porphyrion, who was the antithesis of Zeus. The eldest, Alcyoneus, was born to oppose Hades, the eldest Olympian. The Olympians called upon the aid of Hercules after a prophecy warned them that they would need the aid of a mortal woman's son. Athena, instructed by Zeus, sought out Hercules and requested his participation in the battle.
The Olympians fought the giants with the Fates' assistance before the aforementioned prophecy was made. This means that the giants would have overcome them if Hercules hadn't fought.
List of Giants
Some of the giants identified with individual names:
- Alcyoneus: Eldest of the giants, killed by Hercules.
- Porphyrion: King of the giants, wounded by Zeus and killed by Hercules (later brought back to life).
- Clytius: Immolated by Hecate with flaming torches.
- Damasen: peaceful giant, bane of Ares. Banished to Tartarus by his brethren
- Enceladus: killed by Athena (later brought back to life).
- Ephialtes and Otis: Tricked by Artemis into killing each other, presumably with the aid of Dionysus
- Hippolytos: killed by Hermes, while wearing the invisibility cap.
- Mimas: killed by Hephaestus with a volley of molten iron.
- Polybotes: crushed by Poseidon beneath the island of Nisyros.
- Thoon: killed by the Fates with clubs of bronze.