The Hekatonkheires (also known as the Hundred-Handed Onees) are a race of humanoid beings, each with a hundred arms and fifty heads. They were one of three sets of children born to Gaia and Ouranos, the others being the Titans and the Elder Cyclopes. They were the primeval gods of violent storms, while their brothers, the Elder Cyclopes, held power over thunder and lightning.
Before the First Olympian War, the Hekatonkheires were imprisoned in Tartarus by Ouranos alongside their brothers: the Elder Cyclopes. They were guarded and tortured by Kampê until Zeus killed her and Poseidon freed the brothers by breaking their chains with his Trident. The Hekatonkheires helped the Olympians win the First Olympian War. Two of them, Cottus and Gyges, later served as guards to Tartarus' entrance. Briaries now lives in the underwater forges where Tyson works.
- Briares currently works with the Cyclopes in the underwater forges.
- In Percy Jackson: Sea of Monsters, a Hekatonkheire is seen serving at a café where Percy Jackson, Annabeth, Grover and Tyson to café. Here, however, he is shown with eight hands and one face instead of one hundred and fifty respectively.