Tritannus

The main antagonist for the fifth season. He is Aisha's cousin, the son of King Neptune and Queen Ligea, and the brother of Prince Nereus. He was once a normal merman who was sent to prison after trying to kill his twin brother Nereus (who was chosen to be King Neptune's heir to the throne instead of Tritannus) and was stripped of his prince title. He was later mutated into a horrible monster due to toxic pollution and wanted to rule the whole Magic Dimension by absorbing more pollution to become more powerful and by trying to gain the ultimate power of the Infinite Ocean itself. He stole Daphne's Sirenix powers and gave it to the Trix. He and Icy used to flirt and later entered into a romantic relationship, much to the annoyance of Stormy and Darcy. But he betrayed Icy after he activated the Emperor's throne and gains the ultimate power of the Infinite Ocean, which turns him into a monster in both body and spirit. In the end, he is defeated by the Winx after Bloom destroys his Trident where all of his evil powers were stored. Tritannus is banished to Oblivion for his actions, but in the movie Winx Club: The Mystery of the Abyss, he is freed by the Trix in order to get the ultimate power of the Infinite Ocean, the black pearl.