The Powers shown throughout the series by a variety of characters.
Mermaid Princesses' Powers
Lucia Nanami: Like the rest of the mermaid princesses, Lucia needs her pearl in order to transform into her idol form. Her pearl is also needed in order to summon Aqua Regina. When in her idol form, her voice was transmitted by a microphone like object called the e-pitch, in order to defeat the enemies. Her voice is shown to be very powerful. She is also shown wearing Aqua Regina's outfit in the last volume of the manga. Her hair is loose. She also holds Aqua Regina's staff. Legend of Mermaid was a song that she would sing as child, so this is one of her image songs. Her character songs are Splash Dream, Legend of Mermaid and Koi wa Nandaro. She ends attack songs with the phrase Love Shower Pitch in both the anime and manga followed by 'Encore wa ika ga' which can be translated as How About an Encore?
Hanon Hoshou: Like the rest of the mermaid princesses, Hanon needs her pearl in order to transform into her idol form. Her pearl is also needed in order to summon Aqua Regina. When in her idol form, her voice is transmitted by a microphone like object called the E-pitch and is used to defeat the enemies.
She says Love Shower Pitch in the anime, whereas in the manga she says "Pretty Sugar Pitch!" in order to defeat enemies.
Rina Toin: Like the rest of the mermaid princesses, Rina needs her pearl in order to transform into her idol form. Her pearl is also needed in order to summon Aqua Regina. When in her idol form, her voice was transmitted by a microphone like object called the e-pitch, in order to defeat the enemies.
She says Love Shower Pitch in the anime and in the manga she says "Cool Shine Pitch!" in order to defeat enemies.
It is currently rumored that Rina has been loosely based on real world superhero, The Bird (Halifax, Nova Scotia, Canada).
Karen: In the anime, Karen shouts 'Purple Pearl Voice!' to transform. In the manga, she can transform at will with no incantation. In her idol form, like Lucia and the others, Karen can use her singing voice to get rid of enemies. In manga, at the end of her songs, she uses 'Cutie Hot Pitch' whereas in the anime, she uses 'Love Shower Pitch' like the rest of the mermaids. She has an image song titled Aurora no Kaze ni Notte.
Noel: In the anime, Noel shouts "Aiiro Pearl Voice" to transform.
In her idol form, like Lucia and the others, Noel can use her singing voice to get rid of enemies. Noel's voice matches her personality, calm, and soft. She is not shown to have her own song in the manga or anime, but instead she is usually seen singing along side Coco and Karen. In the manga, Noel has two different hairstyles. In arc one, her hair is middle parted, long and wavy. But when she makes her entrance in the second arc, she has a side fringe resembling Karen's, but on the opposite side.
Coco: In the anime, Coco shouts "Yellow Pearl Voice!" to transform. In the manga, Coco does not have a phrase to transform, she simply just transforms with her own will. Coco can sing to fend off enemies. Once joined with the other mermaid princesses, her voice's power increases. In the manga, she can even do so in her mermaid form and without her pearl.
Sara: Among the Mermaid Princesses, Sara is known to be the most powerful due to the combined power of her hatred and status as a Mermaid Princess. Thus she is apparently to be the oldest of the mermaid princesses.
In the anime and manga, Sara shouts "Orange Pearl Voice!" to transform into her idol form. In the manga while she is still evil, she can transform into Black Pearl Voice, while in that form, her hair, clothes and microphone are black in color.
In her idol form, like Lucia and the others, Sara can use her singing voice to get rid of enemies. However, she can also use it to attack the other princesses by singing in front of them. She can also use her voice without being a mermaid or being in her idol form. In the anime, she can also conjure up a powerful beam of frequency coming from her singing voice to stop a powerful tsunami while no other mermaid princess can. She is also much more powerful than all the other mermaid princesses having shown to be immune to their singing and to have caused them all severe pain when she was singing.
Her song is called "Return to the Sea".
Seira: Seira can transform into Orange Pearl Voice like Sara. She is Sara's successor.
Madame Taki's Powers
Taki has the ability to turn into a clam possibly so that she can swim underwater and for protection. She can also predict the future sometimes, but the most of the times that she tries to she fails.
Izuru: She is basically a beautiful woman, combined with a sea monster, to form a monstrous form of a mermaid.
She attacks with water, so she's obviously strongest in the ocean, but she can also utilize her powers when water is nearby. She can create currents, waves, or even transforming the water into sea dragons to attack. When Izuru hears a mermaid's song, the pain is directed towards her heart, and when the song takes effect, she'll clutch her chest and tremble, as if she's afraid of the song changing her heart. She doesn't often cover her ears. Her power of the water is also halted, with water currents steadying and water dragons dissipating during a song.
Eril: In her Water Demon Form, Eriru attacks with black, energy, wavy arrows. She can also manipulate solid objects with her shadow-like powers and create whirlwinds with her spinning.
The rag or bandana on her head protects her cat-like ears from hearing a mermaid's song. However, it only works in Episode/Chapter 2, though, because only one mermaid, Lucia, sang to her, and one mermaid's voice probably isn't loud enough. When two or three or more gather though, her rag probably won't make much of a difference, and she has to resort to using sound systems to block out the music and hurt the mermaids.
Yuri: Yuri is a pianist, like Mitsuki, strangely enough, and gets her powers from playing the piano, which does strange effects to her environment, such as hypnotizing humans who listen to it, or summoning sea creatures. Her music doesn't seem to have a painful effect to the mermaids, only that it is in bad taste to them. When her piano-playing has enough volume, it can block out one or two mermaid's singing. It only works once, of course, during her first appearance, like with Eriru, but with the appearance of another villain is another mermaid to increase the volume of the mermaids' song. Besides, Yuri doesn't "always" have a piano handy. Yuri can also create an energy ball made of water, but she doesn't really physically fight all too much.
Her piano, if she summoned one out of nowhere, like in episode 9, will disappear if the Mermaid Princesses or anybody defeat her. In Episode 25, however, it is a complete exception. Yuri takes her "punishment" willingly, as she accidentally attacked Hippo, and can only think about his safety during the ordeal.
Maria: Maria's powers are based on ice and snow. She uses her power to freeze anyone or anything. She had more abilities to her ice power. For instance, she could freeze whatever and however she wanted. She is shown controlling winter and more powerful when the cold season comes. She can also use spells that can control ice, snow and cold.Sheshe and Mimi: They have two songs called Kuro no Kyōsōkyoku and Yami no Baroque. They were seen using Coco and Noel's pearls which makes their song more powerful. The Black Beauty Sisters are the most powerful servants of Gaito, with a singing voice so strong that the mermaids can barely stand to listen to it. Sheshe is more powerful than Mimi, because she has demostrated all the powers that Mimi has and more that she hasn't demonstrated.
Lady Bat: He can sing a song (Ankoku no Tsubasa) that makes the mermaid princensses and other people hypnotised and unable to protect themselves. After he hypnotise people he bite them to forget everything. He can also hypnotise someone to tell him everything he wants, like he did to Lucia.
He is able to use magic (or something like powerful tricks) as shown when he was hosting a fake magic show to catch Hanon. His magical abilities incude the ability to create objects that sparkle, he can control and consolidate bats, hypnotise people (by making his song to be heard everywhere), create a thick purple fog and make a mermaid princess weak, by using a powerful discoball. He can teleport himself wherever he wants and he can fly by using his wings. When he was in his medium disguise he could levitate himself, without using his wings. He has a sixth sense too, as he could sense the mermaid princesses, when they were fighting the Black Beauty Sisters. He can transform into a lot of bats (as another way of teleportation) and he can transform into human. However he has demosrated more powers like telekinisis, as he can move objects with his mind (when he made a sphere to fly).
He can also control water (hydrokinisis) as he could separate a whole sea into two seas making in the middle of them immense waterfalls. He also, despite being an original demon, from the land, can breath underwater. He has the ability to control weather too, as when he appeared to Coco, Karen and Noel he could change the weather of a very shiny day into a cloudy day and even create a lightning. He can also create yellow, energy ropes that can tie and electrocute someone or even teleport him/her to Michel's lair.Lanhua: She can divide into a dozen smaller versions of herself (which really do not look harmful or dangerous: in fact, very cute) to play a tune that makes the listeners dance until they die. She has a fan that summons glowing flower petals that seemingly makes the victims pose. She can also make a cage of these petals to capture people and fly by using her wings. She can transform into human too.
Alala: Just like the Mermaid Princesses and the other Original Demons, Alala attacks using her songs. When she sings a song, it can send out fire or stars. Alala also has the ability to set fire.
Oh Yeah! Arara- Alala sings this song in her Human Form, this song can make all males fall in love with her. It has no effect on any female.
Star Mero Mero Heart- She uses this song to attack the mermaids. When the Mermaids hear this song, they start feeling awful and are paralyzed just like the other songs sung by the antagonists. In the manga, she can make the Mermaids dream about everything she wants, including nightmares.
His attacks in the manga and anime are fairly different from each other. The only power he has in both the manga and the anime is absorbing entities within his wings. This attack is, in the anime, seen succesful three times, while absorbing Seira, while absorbing the Black Beauty Sisters and while absorbing Lady Bat, Lanhua and Alala. In the anime he absorbed Michal without having to take her into his wings. In the manga he, as addition to absorbing people into his wings, can 'eat' everyone within his wings resulting into 'eating' the Black Beauty Sisters. He did, however, get their memories of the Mermaid Princesses and their human forms.
He is oftenly seen with his flute, and in the manga he plays it multiple times, resulting in his victims to fall in a trance. He is able to imbed words into his fluteplay and used it to try and manipulate Lucia. He can transform his flute into a whip or a bow. The whip spawns multiple ropes and can therefore be used to take out multiple targets at once. The whip is his preferred weapon but he is seen being very skilled with his bow. In the anime, however, he is seen playing his flute only once, playing Mikaru's theme song, and did never use it as a weapon.
In the final battle he summons many fairy-like small minions with a purple body and red eyes. They can knock out the Mermaid Princesses in a few hits, but are taken out easily when Rihito fires the rod of Panthalassa. In the manga he summons six crosses which chain the Mermaid Princesses.