.hack//XXXX (pronounced X Fourth) is a manga serialized in the monthly magazine .hack//G.U.: The World released in September 2006. The manga is based on the original concept of Hiroshi Matsuyama and written/illustrated by Megane Kikuya. .hack//XXXX has various events that differ from the original versions of the first four .hack games, so it is consider non-canonical in keeping with the overall storyline of .hack.