Aki Izayoi is a main character in Yu-Gi-Oh! 5D's, and was one of the Signers. She is also called the Black Rose Witch.
Aki possesses an extremely strong special ability which sets her apart from the rest of humanity, and even the rest of the Signers. This psychic ability enables her to materialize and bring to life monsters and the effects of Duel Monsters cards, allowing her to freely control them similar to Yami Bakura and Juudai Yuuki.