Crius was one of the Titans, son of Uranus and Gaea. He married Eurybia, daughter of Pontus and Gaea, and had three children, Astraios, Pallas and Perses.
Crius was considered one of the four pillars that hold the heavens and the earth apart. He represented the pillar of the south, while the other three pillars were personified by his brothers Iapetus, Coeus and Hyperion. The four brothers had an important role during the dethroning of their father, Uranus; as they were in the four corners of the earth, they held Uranus in place, while their brother Cronus castrated him with a sickle that their mother had given them.
In the Titanomachy, the war between the Titans and the Olympians, Crius participated siding with the Titans, but did not have a specific role. When the Titans were defeated, Crius along with the rest of his siblings was thrown into Tartarus, the lower level of the Underworld.
See Also: Titans, Uranus, Gaea, Eurybia, Iapetus, Coeus, Hyperion