Eos

Eos (Ἠώς in Ancient Greek) is the Titaness of the dawn, and a daughter of Hyperion and Theia. She and her siblings Helios (the Sun) and Selene (the Moon) were numbered amongst the second-generation Titan gods. Her Roman Counterpart is Aurora. Dew was said to be Eos's tears due to the lost of her son Memmos in the Trojan War.

History
Eos rose up into the sky from the river Okeanos at the start of each day, and with her rays of light dispersed the mists of night. She was sometimes depicted riding in a golden chariot drawn by winged horses, at other times she was shown borne aloft by her own pair of wings.

Eos had an unquenchable desire for handsome young men, some say it was the result of a curse laid upon her by the goddess Aphrodite. Her lovers included: Orion, Phaeton, Kephalos, and Tithonos, three of which she ravished away to distant lands.

The Trojan prince Tithonos became her official consort. When the goddess petitioned Zeus for his immortality, she forgot to also request eternal youth. In time he shrivelled up by old age and transformed into a grasshopper.

Eos was closely identified with Hemera, the primordial goddess of day. In some myths--such as the tales of Orion and Kephalos--Eos stood virtually as a non-virginal substitute for Artemis.

The Curse of Eos
Aphrodite placed a curse upon the Titaness Eos, because she had slept with Ares. This curse filled her heart with constant passion, causing her to fall in love with a train of mortals: Orion, Tithonos, Kephalos and Kleitos.

The Titan's Curse
She is mentioned when Percy calls five o'clock in the morning "an ungodly hour, unless you're the goddess of dawn," though she never directly appears in the series.

Trivia

 * One of her sons, Eosphoros, is sometimes equated with the fallen angel Lucifer, his name meaning light-bearer.
 * She is often equated with Hemera, the Primordial Goddess of the Day.
 * According to some ancient texts it was Artemis who was originally known as the goddess of dawn, this was before people knew that Eos was in fact the Personification/Titaness of the Dawn.
 * The Eos family is a prominent family of main belt asteroids, named after her.