Gorgons

The Gorgons are a trio of sisters, born to an unnamed sea goddess. Only Medusa is known by name.

Medusa
The youngest of the three sisters, Medusa was thought to be the most beautiful. She wore a thin veil over her face. However, unlike her sisters, she was the only one who was mortal. One day, masked assailants broke into the Gorgon realm, and abducted her sisters. When it came to her, however, the intruders threw her aside with disgust, stating that they had no use for that which dies. Angered and humiliated, she went to her mother's temple, and begged the sea goddess to grant her the powers to rescue her sisters. After considering her request, the sea goddess granted her daughter terrible new powers in exchange for her beauty, a decision Medusa has never regretted.

Other Gorgons
Mireska knows of a rumor that Gorgons were being sold at Roseleaf. She passes this information on to Medusa, perhaps indicating that the Gorgons are her kidnapped sisters.

Others
Although they are no longer with her, Medusa's sisters enchant a piece of ancestral armor with their ethereal essence to watch over their youngest sibling.

Trivia

 * The Gorgons in Dota are roughly the same as the Gorgons in Greek mythology.