Keto

A powerful sea monster that is mentioned by Chiron in The Titans Curse.

General
Keto is the daughter of Pontos and Gaia. She and her brother Phorkys, an old sea god, are the parents of the Gorgons Stheno, Euryale and Medusa; of the Graeae (Graiai), also known as the Gray Sisters; of Echidna and of Ladon.

History
The queen of Äthiopia, Cassiopeia, once said she would be more beautiful than the Nereids. Angry because of this, Poseidon sent Keto to cause trouble in Äthiopia. To calm Keto it was decided to sacrifice Cassiopeia's daughter Andromeda. She was chained to rocks and had to see as how came closer. Before the monster stuck, Perseus appeared at the cliff and fall in love with Andromeda with one look. Andromeda told him that she had begged her finance to rescue her, but cowardly, he left. Perseus killed the monster and brought Andromeda to safety. Promptly he asked Andromeda's parents for her hands. Her parents promised him not only Andromeda, but the whole kingdom, for they were grateful for the life of their daughter.

There are different versions of the way, how Perseus killed Keto. In one version he showed Keto the head of Medusa, so that Keto turned into stone. In another version he had to battle Keto and killed her with a magical sword from Hermes.

Keto in Ancient Texts

Keto, or Ceto it is said that has children with Phorcys, as Echidna, Gorgons (which means Medusa, Euryale, and Stheno), and Ladon, and it is also said the the Typhon is Keto's grandson, this things are not yet facts.