Hekatonkheires

The Hekatonkheires, or Hecatonchires (Ἑκατόγχειρες ( "Hundred-Handed Ones," Latinized Centimani), were figures in an archaic stage of Greek mythology, three giants of incredible strength and ferocity, that surpasses that of all of Titans whom they helped overthrow. Their name derives from the Greek  (hekaton; "hundred") and  (kheir; "hand"), "each of them having a hundred hands and fifty heads" (Bibliotheca). Hesiod's Theogony (624, 639, 714, 734–35) reports that the three Hekatonkheires became the guards of the gates of Tartarus.

In Virgil's Aeneid (10.566-67), in which Aeneas is likened to one of them, Briareus (known here as Aegaeon), they fought on the side of the Titans rather than the Olympians; in this Virgil was following the lost Corinthian epic Titanomachy rather than the more familiar account in Hesiod.

Other accounts make Briareus or Aegaeon one of the assailants of Olympus, who, after his defeat, was buried under Mount Aetna (Callimachus, Hymn to Delos, 141).

In Hesiod
According to Hesiod the Hekatonkheires were children of Gaia (Earth) and Uranus (sky). They were thus part of the very beginning of things (Kerenyi 1951:19) in the submerged prehistory of Greek myth, though they played no known part in cult. Their names were Briareus Βριαρεύς the Vigorous, also called Aigaion Αἰγαίων (Latinized as Aegaeon) the "sea goat", Cottus Κόττος the Striker or the Furious, and Gyges Γύγης (or Γύης Gyes) the Big-Limbed. If some natural phenomena are symbolized by the Hekatoncheires then they may represent the gigantic forces of nature that appear in earthquakes and other convulsions or in the motion of sea waves (Mayer, Die Giganten und Titanen, 1887).

Soon after they were born their father Uranus threw them into the depths of Tartarus because he saw them as hideous monsters. In some versions Uranus saw how ugly the Hekatonkheires were at their birth and pushed them back into Gaia's womb, upsetting Gaia greatly, causing her great pain and setting into motion the overthrow of Uranus by Cronus, who later imprisoned them in Tartarus.

The Hekatonkheires remained there, guarded by the dragon Campe, until Zeus rescued them, advised by Gaia that they would serve as good allies against Cronus and the Titans. During the War of the Titans the Hekatonkheires threw rocks as big as mountains, one hundred at a time, at the Titans, overwhelming them.

Briareus as the "sea-goat" Aegaeon
The sea-goat Aegaeon "cannot be distinguished from Hesiod's Briareos", according to M.L. West. They are already explicitly linked in Iliad I.402-04, though they must have had separate origins: Achilles speaks to his mother the sea nymph Thetis of "the monster of the hundred arms whom the gods call Briareus, but mankind Aegaeon, a giant more powerful even than his father." The episode is found nowhere else in Greek mythology. The Olympian gods were trying to overthrow Zeus but were stopped when Thetis brought Aegaeon to his aid -"at one time he must have shared with the goddess dominion over the depths of the Aegean Sea". (Kerenyi 1951:24). "He squatted by the Son of Cronos with such a show of force that the blessed gods slunk off in terror, leaving Zeus free."

Scholia on Apollonius of Rhodes (i. 1165) represent Aegaeon as a son of Gaea and Pontus, the Sea, ruling the fabulous Aegaea in Euboea, an enemy of Poseidon and the inventor of warships. In Ovid (Metamorphoses (ii. 10) and in Philostratus' Life of Apollonius of Tyana (iv. 6) (Theoi.com) he is a marine deity. Hesiod reconciles the archaic Hekatonkheires with the Olympian pantheon by making Briareos the son-in-law of Poseidon who gave him "Kymopoliea his daughter to wed." (Theogony 817).

In a Corinthian myth related in the second century CE to Pausanias  (Description of Greece ii. 1.6 and 4.7), Briareus was the arbitrator in a dispute between Poseidon and Helios, between sea and sun: he adjudged the Isthmus of Corinth to belong to Poseidon and the acropolis of Corinth (Acrocorinth) sacred to Helios.

Adaptations
Briareus is mentioned in the Divine Comedy as one of the Titans who attacked Jove on Olympus. He is in the pit of the giants in the ninth circle of hell (Inferno XXXI.99). The giant is also mentioned in Cervantes' Don Quixote, in the famous episode of the windmills.

Briareos is mentioned in Book I of John Milton's Paradise Lost alongside Typhon as an analogue to the fallen Satan.

Briareos is also a character in the Anime and Manga Appleseed, where he plays a human who has been transformed into a Hecatonchire cyborg body, which also allows him to remotely control 100 systems. This is one of the many references to Greek mythology in the series.

Briares appears in the Percy Jackson and the Olympians novel Battle of the Labyrinth. He was imprisoned in a part of the Labyrinth that corresponds to Alcatraz and again guarded by Kampe. His brothers have died, causing him to give up hope and refuse the chance to escape his prison. He eventually overcomes his despair and fights against the Titans again.

A summonable entity in Final Fantasy XIII is called Hecatoncheir and is summonable by Oerba Dia Vanille.

It is also an "epic" monster in Dungeons & Dragons, that is commonly used by deities to kill other gods, keeping in line with the power of the Hekatonkheires and their strength.