The Sirens appear in the game Endless Fables: The Minotaur's Curse.
The Sirens were once beautiful women who lived in a lighthouse on a magical island separated from the rest of the world. They spent much of their time staring at their own reflections in their mirrors. They also loved singing and playing the harp. Their friends, the Muses, were even more beautiful. They often visited the Sirens.
Many artists wrote songs and poems about the Muses' beauty. The Sirens were jealous, so they stole one of the books written for the Muses. When the Muses found out, they cursed the sisters. The Sirens were turned into ugly mermaids that would forever be chained to the sea. Since then, the Sirens have taken their anger out on sailors who wandered too close to their home.
Centuries later, a human came to the island. In order to get across a gorge, she needed to call the hippocampus. The hippocampus could only be summoned by the song of the sirens. When she reached the cursed sisters, they each asked for an item to help relieve them of their misery; a comb and a mirror. The third Siren revealed that the sisters were remorseful for their greed and envy. She asked the human to return the stolen book to the Muses' chest. Once the book was returned, the Muses' shrine disappeared and the Sirens transformed into beautiful mermaids.