Koronis

Koronis is a lover of Apollo and the mother of Asclepius.

History
Koronis was the daughter of King Phlegyas of Lapinths and Cleophema, the daughter of Zeus and Erato, the muse. One day, Apollo saw Koronis and fell in love with her, they slept together and Koronis got pregnant. Apollo had left a raven, which was white at the time like the rest of those birds, to guard her before leaving. Then Koronis, against her father's warnings, fell in love with a man named Ischys. When the raven found out, it went straight to Apollo. He got so angry he scorched the birds feathers as punishment for being a tattletale and failing to peck Ischys' eyes out, that's why ravens are black today. Then he sent Artemis to kill both Ischys and Koronis because he couldn't do it himself. However, Apollo was able to save Koronis' baby, he became Asclepius, the god of medicine.

The Tyrant's Tomb
While Apollo, who was turned into a human, Meg McCaffrey, and Reyna Ramírez-Arellano were climbing Sutro Tower, they were attacked by ravens sent by Tarquin.

Trivia

 * Another woman named Koronis, spelled Koroneis in Percy Jackson's Greek Gods, appeared as the lover of Poseidon. The god of the sea chased the woman for love, Koroneis prayed to Athena for help and the goddess turned her into a raven. That is why Koroneis is Greek for Raven.
 * Both women's names can also be spelled as Coronis.