Vanitas (voiced by Haley Joel Osment) is Master Xehanort's evil apprentice and is the darkness from Ventus's heart. Vanitas also is the source of the Unversed. Most of the time, he is seen with a mask on, but without it, he looks exactly like Sora. This is due to Sora's heart connecting with Ventus near the beginning of the game, and had anyone else connected with Ventus's heart, Vanitas would look like that person. His plot was to make Ventus strong enough so that they would merge and create a powerful weapon called the χ-blade. Even though he was successful, he was defeated by Aqua and King Mickey Mouse in a physical battle, and by Ventus in a metaphysical battle.
- Vanitas will make a surprise appearance in Jeffrey, Jaden and Scooby Doo on Zombie Island.
- Vanitas will guest star in Jeffrey, Jaden & Friends' Storm Adventures of Dinosaur.
- Vanitas will return for revenge in Jeffrey, Jaden, and Friends' Storm Adventures of The Hitchhiker's Guide To The Galaxy.
- Vanitas will guest star in Jeffrey the Master.
- Vanitas will guest star again in Jeffrey, Jaden & Friends join Men in Black, and Jeffrey, Jaden & Friends' Storm Adventures of Men in Black II.
- Vanitas will become Hiccup's enemy in Jeffrey, Jaden & Friends' Storm Adventures of How To Train Your Dragon 2.
- Vanitas will play Gaston in Beauty and The Beast (Jeffrey, Jaden, Hiccup & Friends' Storm Adventures style).
- In role-playing stories made by tigerman531 and i39darkblade, Vanitas is reincarnated as a little boy and is reformed. He's adopted by Axel and Sailor Mars.
- In the Eds' Adventures series, Vanitas will be reborn from Wonder Woman. He will have no memory of his past and will be raised by Darkblade and Wonder Woman in a better life.
- In the Thunderbolts Adventure Series, Courtney wants to get her revenge on him and Master Xehanort for getting rid of her adoptive family and for giving her that scar under her left ear with the X-blade.