The Empty Box and Zeroth Maria, known in Japan as Utsuro no Hako to Zero no Maria (空ろの箱と零のマリア, lit. The Hollow Box and the Maria of Zero) and colloquially referred to as Hakomari (箱マリ), is a Japanese light novel series written by Eiji Mikage, with illustrations by Tetsuo. ASCII Media Works published seven novels from January 2009 to June 2015 under their Dengeki Bunko imprint. The novels have been licensed for release in North America by Yen Press. Source: Wikipedia (en)