Mitsuari Ayu (蜜蟻愛愉 Mitsuari Ayu?) is a character introduced in Shinyaku Toaru Majutsu no Index. A Level 3 esper with the ability Mental Stinger, she bears an immense grudge against Shokuhou Misaki, who was chosen over her to be developed to Level 5 and was saved by Kamijou Touma when she wasn't. She is the main antagonist of the 11th Shinyaku Toaru Majutsu no Index novel, and represents a contrast to both Misaki's situation and character.