Sword Art Online

(also known as SAO) is a 2009 Japanese light novel series written by Reki Kawahara and illustrated by abec. The series is about many virtual reality worlds.
"Sword Art Online" was commercially successful. According to Oricon, SAO was the top selling light novel series of 2012. More than 16 million copies of the light novel has been printed. The novel was later acted into a Japanese Anime.
An anime television series titled "Sword Art Online" aired in Japan between July and December 2012. It was produced by A-1 Pictures. Its second season called "Sword Art Online II" aired between July and December 2014. The third season of the anime titled "Sword Art Online: Alicization" premiered on October 7, 2018.