Siren

Siren is Hummy's childhood friend and singing mentor, both born and raised in Major land. For years before series start, she was Major Land's Fairy of Songs, and sung the Melody of Happiness every year. However, for the current year, Hummy was chosen to sing it instead. She, allegedly feeling betrayed, defected to Minor Land to ask to become Mephisto's subordinate. But in truth, she was brainwashed as a tool so that he could complete the Melody of Sadness.

She had the ability to shape-shift into any form she wishes, and often alternated between her true feline form and her alter ego Kurokawa Ellen (黑川 エレン), using the pendant on her necklace. She could also summon Negatones from the scattered musical notes using the pendant. However, after becoming Pretty Cure, she has lost her pendant and thus both of these abilities.

Ellen's alter ego is Cure Beat (キュアビート). She uses the light blue Fairy Tone Lary to transform. Her catchphrase is "Can't stop my heart's beat!".

Betrayal
Siren, feeling betrayed by Aphrodite because she chose 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 stealing the Legendary Score and rewriting the notes to create the Melody of Sadness. He then Called forth Siren to sing the new melody. Aphrodite was shocked over her betrayal as she began to sing causing the crowd to start crying and feeling sad. Aphrodite stops the song and spreads the notes to the land where warriors are born. Mephisto sends Siren and the Trio the Minor after them.

First Encounter with Pretty Cures
Siren, in the guise of Ellen, meets Hibiki first and is eager to take the G Clef sealed in her heart. Hibiki runs outside only to see Kanade holding a record the two girls used to listen to together. Siren sees Kanade has the same G Clef as Hibiki and orders the Trio the Minor to take Kanade's while she takes Hibiki's. Before they even reached the G Clefs, the emblems suddenly shone, throwing back Siren and Trio the Minor. As she regains her footing, she sees one of the notes from the Legendary Score on the record and quickly transforms it into a Negatone which calls forth a monster to attack the city and spread the sorrow. Hibiki and Kanade were angered by this, and the emblems in their hearts came out and transformed into Cure Modules, which allowed the two girls to transform into Pretty Cure.

Betrayed Again
During episode 10, Siren was injured and was about to get hit by a car until Ouji saved her. In his presence, she cannot reveal her true nature to him but seemed to have developed a bond with Ouji. The next day, Siren hesitates due to Ouji's presence and one of her subordinates, Bassdrum, transforms the gifts Hibiki and Kanade received into Negatones which they defeat. Afterwords, Bassdrum denounces Siren as their leader. Later, Mephisto declares Bassdrum as the new leader due to Siren's sudden change.

The Big Lie and Being Brainwashed
During Episode 13, Siren sees Hummy telling Hibiki and Kanade about the times when they were still friends. Hummy is able to reach her heart and Siren begins to cry. Then, Falsetto and Baritone appear in disguise, and inform the girls that there is a "Negatone" wreaking havoc in the town. Once Hummy and the girls are out of the way, Siren sees one of the old contestants who tells her that Hummy told the judges for the audition that Siren had given her a fake score. Mephisto appears and tells her the same thing, but Siren still believes in Hummy. She then tried to oppose him but Mephisto brainwashed her again, making sure he erased her memories of being with Hummy and becoming a tool to serve him.

Rebirth and Regret
After Siren obtains the Fairy Tones and the scattered notes, Mephisto invades Kanon Town and sets up a stage to perform the Melody of Sorrow. Aphrodite speaks with Hibiki and Kanade, asking them to believe in Hummy. However, Hummy is kidnapped by Mephisto and is given headphones to amplify the Melody of Sorrow. As Hummy nonetheless expresses her words of friendship to Siren and sings, Siren remembers the good times she spent with her and is moved to tears. As Mephisto tortures Hummy with the Melody of Sorrow, Sirien turns against him and tries to free the Notes, but Mephisto turns them into a Negatone. Hummy manages to free herself and the Fairy Tones, allowing the girls to transform. As Mephisto targets Hummy yet again, Siren calls out and transforms into the Pretty Cure of Miracles: Cure Beat, whilst Hibiki and Kanade defeat the Negatone. Siren, however, is unable to take everything in and runs off.

Everyone becomes curious as to how Siren became a Pretty Cure, especially Siren herself, who finds she can no longer transform into a cat or change her disguise. Left confused as to where to go, she winds up at the church where Mr. Otokichi gives her comfort. Hummy finds her, but she feels she doesn't deserve to be forgiven so easily. As Hummy follows her around, with Hibiki and Kanade also offering their friendship, they are approached by the Minor Trio who create a Tree Negatone. As the Pretty Cure run into trouble and Hummy is captured, Siren stands to protect and produces a Cure Module, allowing her to transform into the Pretty Cure, Cure Beat. Using her new abilities, she rescues Hummy and defeats the Negatone. After the battle though, Siren is still unable to forgive herself and runs off again.

Forgiveness and Joining the Team
Now known as Ellen, Siren continues to reject Hibiki and Kanade's offer of friendship as she is still unable to forgive herself. She encounters a boy named Mamoru who is hiding from his father. He explains that he ran off with his bag after hearing he was going to work abroad for a year. As Hibiki and Kanade have conflicting ideals to Ellen, they go to search for the father whilst Ellen leaves with Mamoru. Mamoru soon discovers a stuffed animal inside the bag that his father made him and decides he wants to return, helping Ellen realise she's not alone as well. However, just as father and son are reunited, Bassdrum spots a Note inside the doll and creates a Negatone from it. As Bassdrum tries to waver Ellen's feelings, Hummy helps her build up the courage to join in the fight as a Pretty Cure. After defeating the Negatone, Ellen overcomes her worries and officially joins the Pretty Cures.

Appearance
As a cat, Siren has smooth, dark purple fur with lighter purple fur around her neck. She has a pink heart-like marking on her forehead and her back and she has several golden bands tied around her. Like Hummy, she has similar music note markings around her eyes.

As Ellen, she has mid-length dark purple hair, acessorized with a twisted golden band tied around one strand. She has sharp yellow eyes and an angular face. She wears a basic white shirt with a sleeveless, black jacket, a short black skirt, long stockings and small boots.

As Cure Beat, her hair becomes wilder and longer, and is tied to the side with a feathered bow. Her costume is slightly more elaborate than the previous two precures, featuring many more frills. Her boots are knee-length and her gloves are wrist-length and fingerless.

Personality
Before being brainwashed Siren was a kind cat. She always cared for Hummy dispite her being naivee to most things. However she could get very envious of other people's achievements, such as when Aphrodite chose Hummy over her to sing the Melody of Happiness. TAfter being hired by Mephisto she was cold, calculating, un-sympethetic and unwilling to open up to people. But there was still good in her, when Hummy managed to convince her that she was blindly following Mephisto and was being used. Her earphones broke and became Cure Beat.

As Ellen she underwent a dramatic personality change. She was shown to be much kinder, but with this newfound kindness also came a streak of naivety, such as being easily offended or being prone to childish fears. After a chat with Hibiki and Kanade she became exicted at the prospect of starting school. So much so, she spent the whole night practicing her introdctory speech, showing just how passionate and commited she was to being accepted as a friend.

Ellen Kurokawa
Ellen Kurokawa is Siren's human form, which she uses to disguise herself at some points in the story to lower the Harmony Power of the Pretty Cures and to make sure she can get the scattered notes. In this form however, she has shown to be a strong fighter and is able to materialize notes and use them as projectiles.

Cure Beat
" Playing the spirit's tune, Cure Beat! "  爪弾くは魂の調べ！キュアビート！ "Tsumabiku wa tamashii no shirabe, Kyua Biito!"

Cure Beat (キュアビート) is the Pretty Cure alter ego of Ellen. Her first transformation occurred during Episode 21 due to her strong wish to save Hummy, allowing her to transform without a Cure Module. Her official transformation occurred during Episode 22, using her Cure Module along with Fairy Tone Lary.

Cure Beat's attack and purification item is the Love Guitar Rod. With the help of Lary, she can perform Beat Barrier and Beat Sonic. With Sory, she modifies her item into "Soul Rod Mode", and can perform purification attack Heartful Beat Rock.

Crescendo Cure Beat


Crescendo Cure Beat is the upgraded form that Cure Beat attains in Episode 47. The Crescendo Tone is required for this transformation upgrade; in the TV series, as the Crescendo Tone was sealed up by Noise, the eight Fairy Tones Dory to Dodory combined to become the Crescendo Tone to allow the Cures to transform. In this form, the Cures can perform Suite Session Ensemble Crescendo Finale.

Relationships

 * Hummy - Siren was a childhood, close friend of Hummy. They grow up together in Major Land, 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. After she found out the truth, she then apologized to her until she was brainwashed by Mephisto once again. In episode 21, Siren seems to shake this off when she saves Hummy from Mephisto and becomes Cure Beat. Siren notes that her only friend was Hummy, seeking advice from her on how to become friends with Hibiki and Kanade in episode 24. Even thought Siren/Ellen is in her human form Hummy continue to call her by her real name Siren rather then calling her Ellen like Hibiki and Kanade.
 * Hojo Hibiki and Minamino Kanade - After regaining herself as Ellen she became friends with Hibiki and Kanade. Siren seems to have trouble expressing herself to them having only had a friend in Hummy before and having been brainwashed by Mephisto's noise of evil for a very long time. She knows that Hibiki and Kanade are nice and will help them out in a pinch and she likes them even more as she finds out about the girls. She often bursts out what she is thinking but this may change as Siren gets to know Hibiki and Kanade better.
 * Masamune Ouji - Ellen was saved by him when she was about to be hit by a car in her cat form and developed a bond with him. When a sleeping Ouji falls on top of her while Ellen planned for Ouji to skip his birthday party, she was caught by Hibiki, Hummy, and Kanade (who was upset about catching them in such a position). Ellen was embarrassed while trying to get Kanade to understand the situation. When she fails, she ends the argument by calling Kanade "annoying." Later in the series (episode 25), Ellen meets Ouji after she had been recently scared by Hibiki and Kanade, Ouji offers her advice about how to better understand friendship.
 * Shirabe Otokichi - While living in Kanon Town, Otokichi has assisted Ellen in fitting in and living amongst its inhabitants. In episode 28, It is shown that he is the one that gives Ellen the uniform for Private Aria Academy, as well as a school bag. Because of this, Ellen is able to go to school with Hibiki and Kanade. In episode 31, Otokichi lent some books to Ellen on learning how camp outdoors, as well as what zen meditation is. It seems their relationship is because of Otokichi being Aphrodite's Father, and being a resident of Major land he is obliged to help her.

Ethymology

 * Siren - Siren is a reference to Greek myth, specifically the Odyssey where a group of beautiful witches called the "Sirens" would sing to lure sailors to their deaths by making them crash their boat into the rocky shores of their island.
 * Ellen - English variation of Helen, "bright, shining one.
 * Kurokawa (黑川) - The name Kurokawa has two terms. Kuro means black in Japanese, which fits Siren's theme color while Kawa means river. Her name can be roughly translated as Black River.

Trivia

 * Siren is the first mascot-like character to be a villain. She is also the second mascot-like character to become a Pretty Cure, the other being Milk, who obtained status equal to that of a Pretty Cure.
 * She is the first Mascot to be given the title 'Cure'.
 * Siren is among one of the many the villains of the franchise to eventually join the side of the protagonists, the others being Kiriya, The Kiryuu Sisters, Bunbee and Higashi Setsuna.
 * Siren is the second villain to become a Cure, the other being Setsuna.
 * Siren also has a human form like the mascots from Yes! Pretty Cure 5, Yes! Pretty Cure 5 GoGo!, and Coupe from Heartcatch Pretty Cure. She first introduces herself in this form to Hibiki as Ellen.
 * Although her main form is Ellen, Siren also seems to be able to disguise herself as any human, she is seen doing this to try to fool the Cures.
 * Siren is the only mascot character besides Hummy to be a cat.
 * Siren as Ellen once used her abilities to decrease Hibiki and Kanade's Harmony Power by disguising herself as a transfer student named Houjou Sakura.
 * The necklace Siren used to transform into different forms broke when she first became Cure Beat, resulting in her being "stuck" as a human.
 * It is revealed in episode 24 that Siren/Ellen is afraid of crabs, which Hibiki and Kanade refer to as cute.
 * Siren/Ellen is similar to Miki with both sharing a blue theme colour and a fear of underwater animals. (Miki's being octopuses and Siren/Ellen's being crabs.)
 * While Hibiki, Kanade and Ako refer to Siren by her human form's name, Ellen, Hummy, Trio de Minor and most other Major Landers refer to her as Siren, her true name.
 * The power behind Siren's form changing necklace is unknown.
 * Siren/Ellen is the lightest among the three (Hibiki, Kanade and Siren/Ellen).
 * Siren/Ellen cat form is similar to Cure Muse's Cure form.
 * Siren/Ellen/Cure Beat starred in Pretty Cure All Stars DX: 3D Theatre.