The Witches of Winx Club (commonly referred to as the "Trix") are a trio of relentless evil-doers, who are constantly seeking power over the universe. In their attempts, they have allied with other villains such as Darkar - and Valtor, hoping to rule the world alongside these like-minded people. The three attended Cloud Tower until they got to their senior year, in which they considered the school beneth them, disobeyed the rules, and therefore got kicked out. Below, you can be introduced to what the characters look like - as well as their different power-stages as the series goes on.
Given the the witches by Darkar, to help counter the Winx Club girls' Charmix powers. They are given a glowing piece of magic that snakes itself around the user, and enhances their magic.
Hence the name, this is the power given by Valtor to help overpower the Winxs' new Enchantix magic. This transformation consists of a complete change of outfit, and a much higher level of magic.