Omega Dimension

The Omega Dimension is a frozen dimension that serves as a prison. The worst criminals from all over Magix are sent to this desolate place, deeply frozen and abandoned, in this supposedly "escape-proof" prison. Tecna was once trapped in the Omega Dimension. Luckily, as Tecna earned her Enchantix and combined it with her technology, making a survival suit, turning ice into food and keeping her warm until Bloom and Sky found her.

Season 3
This place was first introduced at the beginning of Season 3 when the Trix were sent there. Icy was able to free her sisters and herself, thanks to her power over ice. It was there where they first meet Valtor, the main villain in Season 3.

To escape, they broke open the portal which was linked to Andros, Aisha's home planet. Rumors spread that if the portal didn't close soon, Andros was going to be destroyed, because the energy of the Omega Dimension and that of Andros are of opposite nature.

The Winx arrived to close it, but it was Tecna, who went inside the vortex generated by the portal, and closed it, earning her Enchantix, but also falling inside in the process. The Winx believed that their fellow friend was dead, but Timmy trusted his instincts, which told him that Tecna was alive.



It was later revealed that she was stuck in the Omega Dimension. When the Winx and the Specialists go there to find Tecna, it's revealed that some prisoners who escaped their ice cells were ruling the planet. Thanks to Bloom, who lead the Ice Serpent, who is the main guardian of the Omega Dimension, towards the prisoners, they were once again frozen. After the Winx leave, no more about the Omega Dimension was heard in that Season. According to Bloom, the frost/guard snakes maintain the magical balance of the Omega Dimension.

Season 4
Omega Dimension is where the Winx and the Wizards have their final battle, and also where the Wizards of the Black Circle meet their end. After being defeated for the final time by the Winx and Nebula, Ogron, Anagan, and Gantlos are frozen themselves there, never to be seen again after they fall in a ravine, when the ice around them crumbled because of the rage of the final battle. Nebula wanted to remain there as a punishment to herself, because she thought that her wish for revenge against the Wizards had made her like them, but was convinced by Bloom that she was not evil and that there was still some light in her heart, and she returned with the Winx to Morgana, who then forgave her. After this the Winx were reunited with Aisha and a ray of sunlight appeared there, upon which Brandon noted that sun rays are rarely seen in the Omega Dimension and that one appeared as it was a special day.

Trivia

 * Omega is the last letter of the Greek alphabet, denoting the sound ō, and written as "Ω" (capital form), and "ω" (minuscule form). Being the last in the Greek alphabet system, it is usually symbolically used to denote the end of something in contrast to the letter alpha, the first letter of the Greek alphabet, which represents the beginning of something.
 * It is implied by Gantlos that the Omega Dimension is at the end of the Magic Dimension.
 * Obsidian, since evil creatures are imprisoned there and is made of only one material, obsidian stone, is similar to the Omega Dimension where all the worst criminals of the Magic Dimension are sent and which is made entirely of ice.
 * However the Omega Dimension appears to be more mild, as it is frozen one may even survive there and only criminals are sent there while in Obsidian everything that is not evil is destroyed, and even the evil ones suffer, as the three old witches lost their bodies, and not only are the most evil creatures imprisoned there, they are also spawned there, like the Ancestresses were.
 * The guardian of Obsidian, Mandragora, is also a servant of evil while the guardian of the Omega Dimension, the Ice Serpent, is neutral and is neither good nor evil.