Hundred Handed Ones

Appearance
The Hekatonkheire, also known as the Hundred handed ones, were three incredibly huge and strong Giants with fifty heads and a hundred hands on their body. Their names were Cottus, Briareus, and Gyges.

Origin
They were the last of the 18 children of Uranus and Gaia, the others being the Titans and elder cyclopes. The Hundred Handed Ones supported the Titan Cronus's conquer of his father, after they were imprisoned by Uranus and guarded and tortured by Kampe.

However it was not until the Olympian war, when Gaia foretold that with the Hekatonkheire's help Zeus would be able beat Cronus, that they were freed by Poseidon, who broke their chains with his trident. After that, they fought against the titans alongside the Olympians and won. Briareus was later singled out as the "good one" by Poseidon and was given a wife.

Riordanverse
By the time the second Olympian war hit Briareus was the only Hekatonkheire left, the other two had guarded the entrance to tartarus before they faded. Tyson, Percy's cyclops brother, freed him from Alcatraz, where he was imprisoned. Today he works in the underwater forges with Tyson.