Cloud Tower is a boarding school for witches. It is the magical competitor and rival of Alfea. Its headmistress is Headmistress Griffin. The campus itself is a huge and vast organism.
Cloud TowerCloud Tower School for Witches is proud to have turned out some of the wickest witches in the universe. With a stellar offering courses in Mayhem, Hexes, and several levels of Advanced Evil, Cloud Tower is the pinnacle of education in the dark arts.
Cloud Tower is hard to enter, as there is a defense field surrounding it. There are ways of getting past this defense, however: tunnels that connect the schools, ways to get past the field itself, and one may enter if one is invited, for example, Baltor transforming into a stag chased by wolves (actually the Trix). Along with that, the tower can be manipulated like a high tech confusion device bya person in the main office. This twists the building into forming new corridors or passages to confuse all those inside.
Cloud Tower does not appear much in season 2, except in 9th episode, when Tecna goes to meet Miss Griffin when she suspects the professor Avalon of being an evil creature. When she goes to ask miss Faragonda when the three magical planets that will reveal Avalon's real form will align next, she is told that miss Griffin is an expert in Astronomy.
The Tower appears again when the Winx are temporarily transferred there to protect the Codex piece kept there. The Winx, with Mirta as guide, then have to learn using their dark feelings for the witchcraft hearts, much to their inconvenience, as they are usually taught to use their positive feelings in classes at Alfea. It is also revealed that Cloud Tower is not only a building, but also a living creature with a heart, the moats being its roots and the towers its branches, and that it was a magical entity created by extremely powerful witches. Meantime, Mirta and Lucy manage to reconciliate. The Tower is infiltrated by the Trix who, under the orders of Lord Darkar, try to claim the codex of Cloud Tower. Initially, the Trix manage to take control of the Tower, causing it to modify its structure according to their wishes. Later Miss Griffin gains control of the Tower and orders it to come back to its former structure. After much fighting and wandering in the school, the Winx finally find the location of the Codex and fight the Trix for it but they unable to control the spell they were initially aiming at the Trix and it explodes on themselves, allowing the Trix to steal the Codex fragment.
Cloud Tower appears for a last time in the 25th episode of the season, where miss Faragonda contacts miss Griffin to inform her about Lord Darkar who kidnapped Bloom to gain the Ultimate Power. Miss Griffin accepts to fight together with Faragonda, Codatorta, the Winx and the Specialists against the Ruler of ShadowHaunt. After Darkar's defeat, all the witches of Cloud Tower go to the party organised at Alfea, having apparently put aside their rivality with the fairies after the Winx girls' temporary transfer there (Mirta mentioned, prior to the Winx going to Cloud Tower, that the Cloud Tower witches did not like working with fairies because they think that fairies have easy lives at Alfea).
In Season 3 The Trix and Baltor ruled over Cloud Tower again and Cloud headmistress, Ms. Griffin, was trapped and the witches were cursed by Baltor and were forced to attack Alfea, but was repelled. After a while Baltor left Cloudtower and went on to a new hideout. He made Cloudtower disappear the next episode and the Winx Club used their fairy dust to restore the school.
Griffin is the headmistress of Cloud Tower.
Professor Ediltrude is a witch that teaches Hexes at Cloud Tower and sister of Zarathustra.
Professor Zarathustra is a witch that teaches Mayhem at Cloud Tower and sister of Ediltrude.
Icy is a former student. She was expelled.
Darcy is a former student. She was expelled.
Stormy is a former student. She was expelled.
Mirta is a former student. She transferred to Alfea in season two.
Lucy is Mirta's only friend at Cloud Tower and was also an underling for Icy, Darcy and Stormy.
There are at least 20 unnamed witches in Cloud Tower.