The Trix are an evil trio of witches, and the main antagonists of the show, who attended Cloud Tower in the first season until they got expelled. They are the enemies of the Winx Club. The Trix are sisters who descended from the Ancestral Witches. They were arrested in the end of the first season after an attempt to invade Alfea failed, but they escaped with the help of Lord Darkar in the beginning of the second season. In the third season, they worked with Valtor, but in the end, were arrested again. The Trix did not appear in the fourth season. They made a comeback in the second film as minions of the Ancestral Witches. The Trix are practically the 'bullies'. The three sisters truly despise and hate the Alfea fairies with all their hearts.
- Icy : The leader and eldest of the trio, her name refers to her powers of ice. She enjoys torturing pixies for the sake of torturing them. Icy despises Stella and Bloom, therefore she is most competitive with the two for the whole series. She is the most powerful of the three. In comparison to her sisters, she is more aggressive than Darcy, but calmer than Stormy. Icy wishes to rule the whole universe, just like her 2 sisters. Icy often considers herself as the best out of all three of them, and she tends to torment her other sisters when they fail on doing something and she succeeds. Icy tends to steal the spotlight from Darcy and Stormy, no matter who thought of the plan. Darcy and Stormy are often forgotten, and Icy is mostly mentioned. Despite wanting the spotlight to herself, Icy has always shown she'll always need her sisters by her side whenever a plan is hatched. Icy's polar opposite is Bloom, whose powers are related to fire, and her own are ice related.
As shown, Icy wears a teal blue-ish one-piece suit, with a royal blue cape and teal blue, knee-high boots. Icy also wears a pair of fingerless gloves, similar shades to her suit. She is also wearing a blue choker necklace that's connected to her belt, and an 'I' is placed over her stomach, becoming a part of her belt. Her hair is in a high ponytail which is held by a dark teal tube piece. Icy wears teal-ish eyeshadow and pink lipstick.
- Darcy : Darcy's powers works with all forms of darkness, including illusions, as her name
suggests ("Darcy" meaning "Dark One"). Darcy has been described as the "Lady of Darkness", "Queen of Darkness" and the "Queen of Dark Magic". She enjoys tormenting fairies and is less aggressive than her sisters. Darcy hypnotized Riven, getting him to turn on the fairies, for most of season one. Darcy is skilled with discovering weaknesses of her opponents and exploiting them. It was hinted that she had a crush on Riven, as she has described him as cute and saved his life from the his bike incident. She may be less aggressive than Icy and Stormy, but she is the most cunning. Her polar opposite is Stella, whose powers are based on light.
Darcy has long, brown hair and bangs that reach to her waist, that is a lighter shade of brown. Darcy's witch outfit is an indigo tube-styled bodysuit with capri trousers. She wears ankle boots that's similar shade with her bodysuit. She also wears purple gloves, and a choker necklace connected to her belt, similar to Icy's and Stormy's, but hers are indigo, and it forms a 'D'. Darcy wears purple eyeshadow and purple lipstick.
- Stormy : The youngest of the trio. Her powers involve lightning, storms, and weather. She has the worst temper of the group and is prone to violent outbursts. She often does not think before she does something. Stormy is Musa's rival for most of the series. Stormy has been described as the "Storm Queen" or "Queen of Storms". She believes she is the strongest out of all three, where in fact, she is the weakest, which she makes up for by being the most aggressive one. Stormy tends to hold grudges and is very quick to anger and rage. Stormy's polar opposite is most likely Flora, who's an earth affinity while Stormy is based on the sky, or Tecna, who's magic is controlled electricity, whereas hers are wild electricity.
Stormy has dark blue frizzy hair, shaped like a cloud, and her lavender bangs are shaped like lightning bolts, which reaches down to her shoulders. In her witch form, Stormy wears a maroon, tube dress that comes down to her mid-thighs. She also wears a maroon, of similar shade as her dress, fingerless gloves, that goes up to her elbows. Stormy wears maroon tights and high-heeled boots, which are longer than Darcy's, but shorter than Icy's. Similar to her two sisters, Stormy also wears a choker that connects to her belt,which forms an 'S' that's placed on her stomach. Stormy wears maroon eyeshadow and lipstick of the similar shade.