Who is Titans from Theogony and Works and Days and what is their importance?

Titans are the sons of Heaven alone. He calls them the Titans in reproach for an unnamed, fearful deed. The Titans are at war with the Olympian gods for ten years until Obriareus, Cottus and Gyes are released from the prison by Earth's advice, and help in the fight against the Titans. The Titans are defeated and bound at the ends of the earth. The Olympian gods hide them under a misty gloom and Posiedon fixes bronze gates around their prison.