Hecatoncheires
Ἑκατόγχειρες
Three brothers with a hundred arms and fifty heads apiece.
Uranus, repelled by their ugliness, buried them in the earth — and Cronus never released them either.
When Zeus set them free, they hurled boulders three hundred at a time and buried the Titans beneath them.
What decided the Titan war was not the thunderbolt but these three brothers. After the war they became the gatekeepers of Tartarus.
SourcesHesiod, Theogony