Their main purpose is to capture all the Earth Fairies and steal their magic powers to become the masters of the Earth. To capture the fairies, they use a magic object called the Black Circle (Item) from which they got their name.
In the end, Duman's power becomes unstable and Nabu kills him. Later Anagan, Gantlos, and Ogron are frozen forever in the Omega Dimension by the Winx and Nebula with Believix Convergence. The intensity of the battle causes the Omega Dimension to collapse, and the three frozen wizards fall into a crevice, never to be seen again.
- Despite being paired together as antagonists of the season, one of them is killed two episodes before the other three are defeated.
- It is unclear whether Ogron, Anagan, and Gantlos fell to their doom in the Omega Dimension or if they survived and remain frozen for eternity.
- Ogron's powers are similar to those of Sebastian Shaw in X-Men.
- Gantlos's soundwave attacks are similar to those of his enemy Musa.
- With his hat and the stripes on his arms, Gantlos looks similar to Freddy Krueger.