Omnia

Omnia is the Supreme Guardian of Sirenix and is one of the nine Nymphs of Magix, powerful guardians of the Dragon's Flame.

Appearance
Omnia looks like a larger, human-sized version of the Sirenix Guardians. She is yellow skinned and mermaid-like with a long and adorned tail. She has yellow hair shaped into an elaborate hairstyle, a pink shell-shaped tiara, some orange bracelets, yellow fins that form a cape behind her and a pink shell on her chest.

Season 5
In "Sirenix," after the Winx have restored the Lake, Guardians of Sirenix open the gate to the Infinite Ocean and Omnia appears in front of it. She is introduced as the Supreme Guardian of Sirenix by the selkies, and announces that the Winx are now Sirenix fairies, before letting them into the Sirenix gate.

After the Winx have transformed into Sirenix and enter the Infinite Ocean, she tells the Winx that as Sirenix fairies, the Infinite Ocean is always open to them. Not long after the Winx explore the Infinite Ocean, she also tells the Winx that as Sirenix fairies they are each granted a wish. The Winx are delighted to hear the news, but Omnia later tells them that there is new evil in the Infinite Ocean, and that they need to fully develop their new powers to rid it.

The Mystery of the Abyss
Omnia directs all the selkies to leave so that Tritannus will not weaken them much more and then Tritannus attacked Omnia and she was weaken and begged Tritannus not to hurt the selkies and told where the pearl of the Abyss was in the Infinite ocean. The Selkies surround her and then the Winx came and she told everything that has happen. She danced at the end when Alfea had a party.

Magical Abilities
Omnia has the ability to reverse any spell, which was shown when she de-mutate the mutants back into jellyfishes. She can also shoot teal beams and create barriers. Also, she can enter and exit the Infinite Ocean through the Sirenix Gate. She is powerful enough to enter the Coral Barrier, hide the Pearl of the Deep, and become its guardian for generations.

Omnia's Lair
Omnia lives in a lair somewhere in the Infinite Ocean. This is where she resides along with the keepers of the ocean gates. In some situations, she creates a powerful bubble barrier that secures it from any danger. It has many rocks and a throne. Also, it has starfishes and plants in it.

Trivia

 * Her name is derived from the prefix omni-, which itself is derived from the Latin word omnis and means all.
 * Because of Omnia's yellow skin, her appearance is similar to Stella's Sirenix Guardian.
 * She and the Sirenix guardians resemble the Undines that had appeared in the first season.
 * Omnia's voice actress in the Italian version also voices Serena and Marion.
 * Omnia had a past with Politea.