The keeper of the Legendarium can summon any number of wild creatures from the book just by reading it out loud. According to Eldora, the Legendarium is a dimension where fictional characters are real, which means, it is a magical link between the imaginary world and the real world. When the Legendarium World is accessed, the legends become real.
AppearanceLegendarium is a brown book which has many patterns, a purple circle with a symbol in the center, a lock, and a hook on its cover. Inside of it has many drawings and stories about the legendary creatures of the Magic Dimension and Earth.
The Legendarium is a book that has the power to bring legendary creatures to life and can make legends come true. An evil wizard named Acheron created it, so he would be the greatest sorcerer of the magical universe, but he could not control it, which trapped him in the book. It was once kept in the Lost Library of Alexandria in Egypt. A Fairy Godmother named Eldora, who guarded the library, was the only one who knew how to lock it. She wrote all its secret in her diary. Subsequently, she brought her apprentice named Selina to the library and accidentally read the legend of the Hawk Spirit, which invoked it. Panicked, she turned it into a pig and Selina returned it back to its book. While Eldora traveled around the world to find a way to lock it, she kept it in her house in the Forest of Flowers securing it with a barrier. Acheron dealt with Selina and told her that he would turn her into a powerful witch, and in return, she must work for him and free him. To prove his power to her, he turned her into the "Witch of Snakes". One night, under a full moon, Selina choose Acheron over Eldora and fled from the forest with the Legendarium.
The Legendarium is first introduced in "The Legendarium" at Cloud Tower by Selina. To show Headmistress Griffin her special talent to be accepted in the school for witches, Selina shows Griffin and the Witches, the Legendarium. After the witch headmistress asked her to demonstrate its power, Selina reads the Gloomy Wood Trolls' legend, and orders them to attack Pixie Village, which they do. They only disappear when Griffin says she saw enough and mentions that the Legendarium is a very powerful and dangerous book. Not long after, the Trix take Griffin's place as headmistresses and make a deal with Selina. If she works with them reading legends when she is asked to, they will give her more power.
In "The Flying School", in an attempt to win Linphea College, the Trix make Selina read the Treants' legend to frighten the college's students. The Linphea fairies try to fight them but instead they get captured by them. The Winx fly to Cloud Tower, to stop whoever started that, but they get attacked by Selina and lose their powers except Bloom.
In "Bloomix Power", the Winx, Daphne, the Specialists, Roy, Nex, and Thoren return to Linphea College to stop the Treants with magical potions concocted by Flora. After the Treants are defeated, Selina reads the Flying Basilisk's legend. While Bloom and the Specialists take care of Cloud Tower, the other Winx, Roy and two of the Paladins have a hard time fighting without the girl's power, even with Miele's help.
In "The Golden Auditorium", the Winx finally succeed to get rid of the Flying Basilisks. As the Winx are at the Golden Auditorium on Melody, Selina, as ordered by the Trix, reads the Pandemonium Sprites' legend. Bloom, Flora, Stella and Aisha got defeated by those creatures, Musa and Tecna lure them to the Pandemonium Cave to use its echoing to defeat them.
In "Vortex of Flames", this time wanting to get rid of Bloom, Selina reads the Fire Eaters' legend. It was only after Bloom was thrown in the Vortex of Flames and passed its test that the Winx can defeat them with Bloom's help.
In "The Lost Library", while the Winx are in Alexandria, Egypt on Earth, Selina reads the Mummies' legend to distract the Winx and give more time to the Trix to find Eldora's Diary before the Fairies. Thanks to Chatta's help, they easily defeat them.
In "Attack of the Sphinx", in order to distract the fairies and give more time to the Trix, Selina reads the Sphinx's legend and goes to the library to search for the diary by herself. The Winx resolve its riddle, again thanks to Chatta, and Bloom found the diary.
In "Shrine of the Green Dragon" after the Trix got caught, Selina reads the Green Dragons of the Great Wall's legend. Lu Wei, at first not wanting to help them, tells the Winx how to tame them and they succeeded to do so.
In "The Fairy Godmother", Eldora tells the Hawk Spirit's legend in a flashback of when Selina was her student. After the flashback, Selina reads the Ectoplasm Specters's legend. Seeing none of the Winx can do anything to defeat them, Eldora recites the legend of the Lenugias, which its power defeated the Trix and the Ectoplasm Specters.
In "The Curse of Fearwood", Selina reads the legend of the Werewolves to defeat the Winx, the Specialists, Paladins and Daphne, so that they could not find the Silver Spear and the Magic Totem in Fearwood. Later, Icy asks Selina to find a legend that she can portray to enter the Legendarium World and lock Flora and Helia in it. Icy then freezes Helia and kidnaps him.
In "The Magic Totem", Icy as the Snow Queen continues her chase with Flora. With Flora's special spell, she left the Legendarium World along with Helia and the Magic Totem. Later in the episode, she follows them into the real world and froze Fearwood over, but Flora uses one of her unique spells to reverse Icy's spell on Fearwood, on Helia and to defeat her.
In "Queen For A Day", Selina unleashes the Magical Mirror in order to make Stella evil. Once she got possessed she started acting like a witch. When, Stella broke the mirror she was back to normal, but Darcy stole her crown and, went to the Legendarium World. Stella followed her in a Mystic labyrinth where Darcy went. Stella was walking through the entrance and saw a person with a mask on who, was actually Darcy in the form of Ariadne. Stella, started flying through the labyrinth and ended up coming in the center. She found herself face to face with the Minotaur bull.