Obsidian, is a realm of the Magic Dimension, and its gate is called the Obsidian Circle. In the 24th episode of the third season, when Bloom goes to Cloud Tower, the Ancestresses' essence remaining there, talk of the Obsidian Dimension without mentioning its name and tell her that it is a place which cannot be reached through magic. It first appears in the first Winx Club Movie. It's the realm of ultimate evil. In this dimension, all the evil creatures live, and are held as prisoners. The French novelization of the movie and the English dub of the first film mentions this place as being the birthplace of the Three Ancient Witches. Somewhere in this place, there's a huge sea of solid rock, in which the inhabitants of Domino were captured.

On top of a rock, Oritel stood and turned to stone. He tried to get his sword, in which Marion was captured or went into. Behind were three caves with faces, in which the Ancestresses lived. Obsidian also has a guard, Mandragora, Witch of the Insects, and its gate can only be opened by a key which is found in the Tree of Portals at the Pixie Village.

If someone who is not evil enters Obsidian, he or she is lost in the power of evil. When the Winx, without Musa, enter Obsidian, they all except for Bloom, get lost. The four fairies then get to see their biggest fear: Aisha gets attacked by her Morphix, Flora gets attacked by dead plants, Tecna gets a headache because her brain receives too much data with no logic at all, and Stella disappears, no one being now able to appreciate her beauty. When Obsidian gets destroyed, the witches are free, and at the end of the movie they fly through a hall, to the Trix. They say they will find bodies to use. In the second Winx Club Movie, they all together disturb the balance of Good and Evil in the Magic Dimension in trying to gain absolute power and are the main villains, but they are destroyed for good by the Winx, and the Trix are again caught.

Description

According to Faragonda, in the first movie, the Obsidian Circle is said to be the secret entrance to a dark and terrible place, a black dimension of ultimate fear and hate, and that the gate of the Realm of Obsidian is what keeps evil distant, adding that this was the place where the Ancestral Witches were generated. When Bloom said that maybe her parents were there, Faragonda replied that it was preferable to hope otherwise as anyone who enters Obsidian is hopelessly lost, corrupted by absolute evil.

in the French dub, there are slight differences, as Faragonda says that the Obsidian Circle is the way to a dark, secret place full of sadness, a passage to a dimension ruled by fear, sorrow and bad luck and that the gate of that realm, the Obsidian Circle, is a terrifying symbol. She also said that all those who enter Obsidian are lost forever, destroyed by the darkest forces.

According to Flora, Obsidian is the nightmare realm where monsters and the most formidable creatures are all caged, and Faragonda precises that it is the story every child of Magix hears when he or she misbehaves.

It was mentioned by Musa as being a forbidden place and Tecna further commented in the French dub that even for those who did the most cruelties, it was the most redoubtable and negative experience ever, and that Obsidian is a rock which annihilates powers of pure magic, sometimes definitely. In the Rai English dub of the first film, Tecna said that unless the Winx were made of pure gold Obsidian would drain their powers, making their chances of finding anything there exactly zero.

Trivia

• Obsidian is a naturally occurring volcanic glass which of usually dark color which has been widely used throughout history to make blades and other cutting instruments.
• Obsidian is known to be the sister realm to Oblivion.
• 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.