Winx Club, Season 6

Eldora:
Selina? Selina, what were you doing?

Selina:
Nothing, just reading.

Eldora:
But that's Acheron! He is the evil sorcerer who created the Legendarium, only to be trapped inside these very pages. You must stay away from this book, Selina! Understood!? But I felt a change in her. She was not the fairy she used to be. An evil power was lurking deep inside her. One night, in the light of a full moon, Selina declared her loyalty and devotion to Acheron. And with that, she stole the Legendarium and fled from the Forest of Flowers. And now I am afraid that Selina is trying to free him.

Bloom:
Well, then we better stop her before it's to late!

Aisha:
Something tells me that even the Trix don't know the whole story.

Eldora:
You're right, Aisha. The Trix have no idea that they are the ones being used.