Chaos;Head (カオスヘッド Kaosu Heddo ), stylized as ChäoS;HEAd, is a Japanese visual novel developed by 5pb. and Nitroplus that was released on April 25, 2008 for the PC. A port of the game, named Chaos;Head Noah (カオスヘッドノア Kaosu Heddo Noa ), for the Xbox 360 console was released on February 26, 2009 followed by releases on the PlayStation Portable, iOS, Android & PlayStation 3. The game is described by the development team as a "Delusional Science NVL" (妄想科学NVL Mōsō Kagaku NVL ).
The game's premise revolves around a high school student named Takumi
Nishijō who unknowingly walks into the scene of a gruesome murder on his
way home. More mysterious events start happening afterwards as more
gruesome murders occur in the area. Takumi struggles to cope with
reality and the delusions he experiences as he tries to avoid getting
caught by the perpetrator behind the chain of murders. Although no
release outside of Japan is planned, an unofficial English fan translation has been released.
The game's story has been adapted into a manga that started serialization on May 21, 2008 in ASCII Media Works' shōnen manga magazine Dengeki Daioh. A second manga adaptation that focuses on Sena Aoi and Kozue Orihara began serialization in Media Factory's seinen manga magazine Monthly Comic Alive on August 28, 2008.
It has been decided for this adaptation to be a side story to the
original visual novel. A third adaptation begun serializing in Jive's shōnen manga magazine Comic Rush magazine on September 26, 2008. The anime adaptation of Chaos;Head by Madhouse aired in Japan between October 9, 2008 and December 25, 2008.