Ouranos

Ouranos (in Greek, Ουρανός) is the Greek protogenos personifying the sky. Ouranos is the Greek word for sky (a cognate of the English word air), Latinized form is Uranus. He is the husband of Gaea alone. He was the first ruler of the universe until overthrown and castrated by his son, Kronos. Ouranos, could (and probably would be) be the greatest villain in Greek mythology, even being worse than Kronos but maybe not as bad as Gaea, since she is his wife and mother.

History
Ouranos and Gaea were the gods of the sky and the earth respectively. They became consorts and brought forth their children: the Cyclopes, the Hecatonchires, and the Titans.

Ouranos didn't care for his children, in fact, he hated them. He hated his children that did not look normal most of all, such as the Hecatonchires and Cyclopes. They were unsightly in his opinion, and he wanted them gone. But he couldn't kill them, because they were immortal. So instead, Ouranos threw the Hecatonchires and Cyclopes into Tartarus and positioned Kampê to guard them. This caused Gaea pain and grief, and she was also furious because they were her children, and because Ouranos cared nothing for them. She asked her children, the Titans, to get rid of Ouranos so she could save the Cyclopes and the Hecatonchires, and only the young Titan Kronos was brave enough to do it. He took a flint sickle/Scythe Gaea made and castrated his father. Nothing was mentioned about Ouranus afterwards.

Other accounts stated that Ouranos pushed the Titans back into Gaea because the Oracle said that one of his children will overthrown him. When he grew up, Kronos cut Ouranos' genitals using the sickle and his genitals became Aphrodite and his ichor became monsters.

Kronos threw Ouranos' remains into the ocean. Aphrodite, the goddess of love and beauty, was born from the foam. It is also said that Ouranos' ichor became the Furies when it fell on the earth.

Personality
Ouranos was a terrible father, and did not care for his children. He was a terrible husband too, because it didn't hurt him that Gaea was so sad about the loss of her children. Though it is possible that Ouranos loves her somewhat as stated in the The Titan's Curse by Atlas, "The sky still yearns to be with the Earth".

Powers
As Ouranos is the Protogenos of the Sky, he presumably is able to control the weather.

He presumably has superior power to most of the Olympians, seeing as he is an elder god and was able to throw many of his powerful children, (the elder cyclopses for example) into Tartarus.

The Titan's Curse
Ouranos doesn't appear in the books, but he is mentioned by the General, that a Titan must hold up the Sky because Ouranos is gone, and the Sky still longs to embrace the Earth. Atlas, a Titan, is assigned this torment as of the First Olympian War.

The Battle of the Labyrinth
He along with Gaea are mentioned by Annabeth and a naiad.

The Lost Hero
Coach Hedge mentioned him when he was telling the story of Gaea and how she convinced Kronos to take a scythe and kill Ouranos. When he said that, Piper looked at the sky, as if seeing if it had eyes and a mouth.

Trivia

 * The 7th planet from the Sun, Uranus, is named after his Roman form.
 * It is mentioned that Gaea cannot be defeated and only kept asleep, however it is unkown why Ouranos actually died when Kronos cut him to pieces. But because the sky still longs to embrace the earth, Ouranos may still be alive in some form.
 * Ouranos is the father of Kronos, who is the father of Poseidon, making Ouranos Percy's Great-grandfather as well as grandfather to children of Aphrodite and ancestor to her half-blood children.
 * He is the father of the Titans through his wife and mother Gaea, Making him the father and half-brother of the Titans.