Sword Art Online is a Japanese light novel series, first written as a web novel series, by Kawahara Reki and illustrated by abec. The light novels began publication on ASCII Media Works' Dengeki Bunko imprint from April 10, 2009. The series has also spawned several light novel spin-offs, multiple manga adaptations, an anime adaptation and multiple game adaptations. A spin-off series, titled Sword Art Online: Progressive, was launched in October 2012. The series expands the story of the Aincrad Arc by focusing on the adventures of Kirito and Asuna throughout each floor of Aincrad.