The Dianoid (ダイヤノイド Daiyanoido?) is a commercial building complex located in School District 15 of Academy City. The primary landmark of School District 15, it is described as a place for the rich and famous. It is used mostly as a shop, and is referred to as a fashionable date spot. It is the primary setting of the 12th Shinyaku Toaru Majutsu no Index light novel volume, where it was aptly turned into a battleground by the carbon-controlling magicians known as St. Germain.