The Cyclopes were gigantic one eyed monsters. The most famous is Polyphemus, the Cyclops blinded by Odysseus. Hesiod mentions only three (not a race or tribe): Arges (thunderbolt), Steropes (lightning), and Brontes (thunder), obviously storm gods.They were born to Gara and Uranus. They were also the first smiths. When Cronus came to power he imprisoned the Cyclopes in Tartarus. The were released by Zeus and fought with him against the Titans. As a reward for their release the Cyclopes gave Zeus his weapons of lighting and thunder. They continued as his workers at Mount Olympus forging his thunerbolts
Arges was killed by Hermes while he guarded Io for Hera
Apollo killed at least one of the Cyclopes to retribution for Zeus killing his son Aesculapius.