Belladonna

Belladona is one of the Ancestral Witches who destroyed Domino and Daphne, according to the French novelization of the first movie. She is Icy's ancestress, as well as one of Valtor's mothers.

Season 1
Belladona, along with Lysslis and Tharma were mentioned as the Dark Forces which destroyed Domino when Faragonda tells Bloom about the Great Dragon. The Ancestral Witches made their first physical appearance in "Bloom's Dark Secret", when Belladona and the other two witches were formed in a false vision made by the Trix to scare Bloom.

Season 3
Belladona and her sisters tell Bloom the truth about her parents.

Season 4
There was a portrait of the Ancestral Witches in the Hall of Enchantments along with the portraits of the other enemies of the Magic Dimension at Alfea.

The Secret of the Lost Kingdom
Belladona was seen in the first film as a spirit trapped in the realm of Obsidian, along with her sisters, Lysliss and Tarma. They command their servant, Mandragora, throughout the movie, targeting Bloom primarily.

Magical Adventure
Belladona appeared in the second movie with her sisters after their escape from the realm of Obsidian. Assisted by the Trix, the Ancestral Witches cause the negative part of the Tree of Life to take over the whole of it, annihilating its positive part with the exception of the positive magic that is contained in a pollen in Havram.

Trivia

 * Belladonna is an Italian word meaning Beautiful Lady, as well as the name for the Deadly Nightshade plant, which according to popular folklore was used by witches to make ointments that helped them to fly to witch gatherings.