Siren

Siren is a friend of Hummy, she was born in Major land. Last year she sung the Major Land's Melody of Happiness. But this year Aphrodite chose Hummy to sing it instead of her. She then felt betrayed and went to Minor Land to ask Mephisto if she could be his servent. Besides being a cat like Hummy she also has a human form.

Betrayal
Siren feeling betrayed by Aphrodite for choosing Hummy to sing the Melody of Happiness goes to Mephisto of Minor Land pledging her loyalty. On the day that Hummy was due to debut as the new singer of the Melody of Happiness Mephisto attacks rewriting the notes to create the Melody of Sorrow. Calling forth Siren to sing the new melody, Aphrodite being shocked over her betrayal, she begins to sing causing the crowd to start crying and feeling sad. Aphrodite stops the song and spreads the notes to a land where warriors are born. Mephisto sends Siren and the Trio of Minor after them.

First Encounter with Pretty Cures
Siren in the guise of Elen meets Hibiki first and is eager to take the note sealed in her heart. Hibiki runs outside only to see Kanade holding a record the 2 use to listen to together. Siren sees Kanade has the same note as Hibiki and orders the Trio of Minor to take Kanade's while she takes Hibiki's. As the strike at the girls an energy throws them all back. As she regains her footing she sees 1 of the notes from the Melody of Sorrow on the record and quickly calls forth a monster to attack the city and spread the sorrow, prompting Hummy to give Hibiki and Kanade the power to transform into Pretty Cure.

Relationships

 * Hummy - Siren was a friend of Hummy but after Aphrodite asked Hummy to sing the song instead of her. Siren felt betrayed and became Mephisto's right hand. She tends to yell at Hummy as to try to argue but Hummy is just so optimistic it doesn't really matter.

Trivia

 * Siren is the only mascot-like character to be a villain.
 * Siren also has a human form like the mascots of Yes! Pretty Cure 5, Yes! Pretty Cure 5 GoGo! and Heartcatch Pretty Cure. She first introduces herself in this form to Hibiki as Elen.