Mirrorworld is a series of a planned five books written by German author Cornelia Funke.
- Jacob Reckless: The protagonist of the book, Jacob is a 24-year-old who discovers a secret world behind the mirror in his missing father's study. Jacob escapes to the Mirrorworld for weeks or months at a time. He views family and friends as a burden, and prefers a life where the consequences of his actions do not harm those he loves. He is historically based on Jacob Grimm.
- Will Reckless: Jacob's younger brother who is very dependent on his older brother. He is historically based on Wilhelm Grimm. The first time Will follows Jacob into the Mirrorworld, he is attacked by a Goyl, a race of stone men that live beyond the mirror. Will's skin begins to turn stone, as he becomes the legendary jade Goyl.
- Clara: Will's girlfriend. They met in a hospital, where Clara was a resident and where Will was caring for his dying mother. She is historically based on Henriette Wild, the wife of Wilhelm Grimm. Clara follows Will into the Mirrorworld to find him partially turned to stone.
- Fox: One of Jacob's few friends. She is a shapeshifter, and mostly she prefers to be a vixen. She travels with Jacob after he saves her life, and understands him at times better than Jacob himself. Fox get the power to shapeshift through a dress she got after saving a vixens life. She is maximum 15 years old, but still a very adult character. She is in love with Jacob. Foxes are given supportive and major roles in 6 of the Grimms' fairy tales.
- Evenaugh Valiant: A dwarf who is the guide for Jacob on his mission to cure Will.
- The Dark Fairy: Kami'en's lover. She created the spell that caused any physical attack from a Goyl to turn a man into Goyl himself. She is despised by the other Fairies for leaving their home.
- The Red Fairy: Sister to the Dark Fairy. She saved a dying Jacob after he had been attacked by Unicorns while treasure hunting.
- Kami'en: The King of the Goyl. The first carnelian to lead the Goyl. An excellent strategist who has led the Goyl to victory over the humans of the Mirrorworld.
- Hentzau: The King's right hand, and a jasper Goyl. He is sent by the King and the Dark Fairy to find the Jade Goyl.
- Albert Chanute: Jacob's former mentor, the closest thing he has to a father-figure.
- Nerron the Bastard: A onyx and malachite goyl with a sassy attitude.
- Nesser: A military private for King Kami'en.