Siren

The Siren appeared in the episode "What Happened to Frederick".

History
She guards the waters of Lake Nostros, whose waters are said to return something once lost. Prince James faces the Siren while trying to get water for Abigail. She tires to seduce him but fails, so she takes the appearance of Snow White. She manages to kiss Prince James but he is still immune to her effects knowing it is not true love. The Siren admits he is the first person to realize that and then tries to drown Prince James. While under water she kisses him again but he stabs her with a knife and she dies, allowing him to collect the water.

Powers

 * She is able to enthrall with her magical charms, take on the appearance of others, and animate the seaweed in her lake.